Rear lights, Garmin units, and various other accessories
When you're riding and stop at a convenience store, a rest stop, a restaurant, etc.,
even if it's a hassle, always take them off before going in
I've had my tool bag stolen before
(a tool bag isn't expensive so I let that one go)
and there was another absurd case where someone I know had their Garmin unit stolen while stopped at an aid station during a Gran Fondo.....
I also recall seeing a story about theft happening on the subway
Some people say I'm being overly paranoid, that I'm just imagining things,
or that I'm making too big a deal out of it, or even lying about it,
but if you get too careless, you really could end up getting robbed