It's all about incentive and opportunity. The Geek Squad employee has a good incentive to do so as it means a $500 payday. Considering these guys' likely pay, that's a decent chunk of change. They also have plenty of opportunity to do so, they handle computers all day long.
The police on the other hand have less of an incentive to do so, unless they were specifically trying to hurt someone. They also have far less opportunity, as they would've already needed a reason to have said computer in their possession.
The police on the other hand have less of an incentive to do so, unless they were specifically trying to hurt someone. They also have far less opportunity, as they would've already needed a reason to have said computer in their possession.