If a shop has free samples, I would reasonably assume you are welcome to take one or two to try to see if you would consider buying. But I wouldn't reasonably a

If a shop has free samples, I would reasonably assume you are welcome to take one or two to try to see if you would consider buying. But I wouldn't reasonably assume they would be OK with me taking all of the samples, even if there wasn't a sign saying so, or any mechanism preventing me from taking all of it. Just the same, it seems reasonable to me that Apple leave the computers unprotected so that customers can try out software on them before buying. It does not seem reasonable to me to install software to secretly take photos of other customers for an art project, whether or not it is explicitly stated. Note that I'm not saying calling the Secret Service is an appropriate reaction to this; just that it is ethically questionable, if not outright illegal.