Counting with Eyes: Cala Millor Deploys AI Sensors — Service or Surveillance?

Counting with Eyes: Cala Millor Deploys AI Sensors — Service or Surveillance?

What the new counting technology on the promenade really delivers and which questions remain open

The municipality of Son Servera has decided to install devices along the Cala Millor promenade to count pedestrian flows. Cost: just under €100,000. Technically, these are sensors with edge computing functionality, i.e., devices that perform parts of the analysis locally. According to the town hall, the goal is better planning of cleaning, security and mobility. Sounds pragmatic — yet a simple but pressing question arises:

A similar debate has arisen elsewhere on Mallorca in Digital Eyes on Mallorca's Beaches: Protection or Surveillance?.

Guiding question: How much surveillance and what technical details are necessary so that the counting improves everyday life in Cala Millor without eroding the privacy of residents and visitors?

An everyday scenario: It is early morning on the seafront promenade, the taverna next to the playground is rolling up its shutters, a garbage truck rumbles past, two retirees with shopping baskets sit on a bench, German-speaking voices mix with Mallorcan chatter. The technology aims to capture exactly such moments — how many people are out and about at what times? Such figures can help: fewer empty runs by cleaning services, more targeted presence of security personnel, better planning of buses in the high season. Related coverage on local projects discusses similar claimed benefits and concerns in Sensors on Mallorca's Beaches: Help for Self-Regulation or Creeping Surveillance?.

But the technology has two sides. Edge computing sounds privacy-friendly because raw images do not need to be stored centrally. Still, it remains unclear what exactly the devices recognize and store: Does the software only count heads, does it register body movements, are metadata like dwell time or movement directions processed? Are camera images held temporarily for statistical purposes or for audits? Who can access the raw data — the municipality, the contracted company, subcontractors? These practical and ethical questions are explored in Who counts us on the beach? When sensors decide how Mallorca is distributed.

From a legal perspective, the EU General Data Protection Regulation is relevant for such projects. Authorities must check whether a Data Protection Impact Assessment (DPIA) is necessary and make the results public. Practically, this means: transparency about purpose limitation, retention periods, technical measures for anonymization and whether face recognition is excluded. The facts communicated so far mention costs and technology, but not these data protection details. Similar trust and legal debates have been reported in Palma, see When Palma's squares are watched: AI cameras, new jackets and the question of trust.

What is missing in the public debate is a sober discussion about deployment limits: Will the counting be used purely for statistics, or also to direct security forces? How are error rates or algorithmic biases (for example due to weather, clothing or group formation) taken into account? Who takes responsibility if the figures lead to wrong decisions — for instance insufficient cleaning on certain days or excessive controls?

Specifically missing information that the town hall should provide: a publicly accessible summary of the DPIA, technical specifications (no face-image-based identification), retention periods for raw data and metadata, the name of the contractor and its subcontractors, and a clear operational concept with contact persons for citizen inquiries.

Practical suggestions Son Servera could implement immediately: 1) Before full deployment, a transparent pilot with clear success criteria and a limited duration (e.g. six months). 2) Publication of an easy-to-understand DPIA and a short technical report. 3) Contractual and technical exclusion of any form of face recognition. 4) Use only aggregated data in a public dashboard — no access to raw images. 5) Independent review by a data protection authority or a local committee made up of residents, business owners and technology experts.

There are practical alternatives or complements to camera-based counting: occasional manual counts, optical flow counters without image data, or privacy-friendly Wi-Fi/Bluetooth signals in aggregated form. Often a combination of methods is sufficient to counter biases and reduce costs.

The municipality's decision to become more digital is not inherently wrong. But in a place like Cala Millor, where many people work, live and vacation, "more data" is not a sufficient argument. Rules, oversight and transparency are needed, otherwise public acceptance may decline. Someone sitting by the sea in the morning and smelling the haze of frying fat does not want to feel constantly observed — they want clean paths and reliable bus connections.

My conclusion: The sensors can be useful — as a tool, not as a pretext for comprehensive surveillance. Son Servera should slow the next step: a pilot phase, a published data protection assessment, clear contractual assurances against identification and a public oversight committee. Then the project has a chance to genuinely improve everyday life instead of sowing mistrust.