Why would the employee ask to involve the police? You can just refuse, period.
If your employer has evidence of a crime they're free to try to convince the police to get involved.
The interesting part is that your boss can't do much if he suspects theft besides calling a criminal investigation. I.e. it is difficult to fire an employee for that.
However, when safety is involved, things change. You can get fired for unboxing with the wrong knife. It is actually a side effect of employee protection laws. The employer is responsible for the safety of his employees, and if the employer have set rules for that purpose, not only he can take serious action if they aren't followed, but he has to, otherwise in case of an accident, he may be found responsible if the rules are not enforced.
So if you really want to fire someone, the best way is to argue that he is putting himself or others in danger. It includes hygiene concerns.
And they can claim they didn't watch it at all? Total surveillance without specific reason and without information and consent is exactly what the law is trying to prevent.
> - Random bag checks, like in programming, is not really random. You either have a particular target or type in mind or you apply it to everyone and bag checks are a lot more invasive than video surveillance.
And that's the whole point. If there's a reasonable suspicion that someone stole something, they can ask to check the bag. The Person has the right to refuse that his bag be checked by company employees and ask to involve the police.