1) A lot of those low-security combination locks are easy to change the combination inadverdently. I've definitely done it.

2) A lot of folks you'd expect to have TSA keys don't. When I worked for USCBP we didn't have them, allegedly for security reasons even though CBP is an actual law enforcement agency and TSA isn't--and we were both DHS. Yep, we carry guns in an airport but TSA keys, no way, that's a security risk. I picked locks when I could and cut them when I couldn't; if I really needed a TSA key because I couldn't get into the bag without damaging it, I had to go bring a TSA employee to unlock the suitcase for me.