A stealth score of 100 is ridiculous (or I'm just not that far) so I can't comment there, but-
People don't have PoV zones of sight, they have a proximity detection score. If your stealth isn't high enough you're immediately detected when you enter their proximity of detection. The Burglary feat is an obvious choice if you can't pick/hack it quick enough while out of their proximity.
Also, pickpocketing actually doesn't factor in stealth unless you use the Ninja Looter feat. You can freely pickpocket people while being detected.
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I mean, I'm saying this but I almost have to assume you already know this if you've gotten to the point where you have 100 stealth. Good luck.
EDIT: just read the Dev saying I should approach someone from behind while stealthed, meaning it probably factors in proximity as well as PoV, pardon the disinformation.