Earlier quoted context omitted.
Some people see the glass half full as they have evidence of their movements as an alibi should they need it.
Or half empty -- as evidence they were somewhere unfortunate (doing something totally benign and unrelated.)
At worst, you're somewhere unfortunate (doing something benign and unrelated) and someone brings you in for questioning about it. Wouldn't they do that in many cases even if your GPS was off (for example, from seeing you on cameras or other means)? It seems better to be able to bring in as many people as possible to get whatever information is needed to help with whatever situation was unfortunate in the first place.
If asked, it's not like you're going to lie and say you were somewhere else if your GPS was off. This way, you at least have proof you were exactly where you said you were.