I am unfortunately flying through LHR so I am checking a small rolling bag for the first time in years, as I have a separate tote I carry...
Questions for the checked bag:
1. Will I need to pick it up at LHR security, or will it be checked through (I am flying AA from ORD to LHR, then BA from LHR to PRG, all same ticket)
2. Is there ANY benefit from using those TSA locks? I will only have clothing in the bag. Is it necessary and do you use it for international flights?
3. Any advice to keep my bag from being tampered with? I usually carryon a tumi or briggs, but given that I have to check, I am going to use an old samsonite so it does not attract attention. (last tumi I checked years ago "fell off the truck").
Although I am a fairly well traveled person checking a bag is a rare occurrence in my life.

I'm not sure I understand... why are you checking a bag? LHR lifted the one carry-on limit several months ago. As long as your bag(s) fit the size restrictions, you should be ok with a rolling bag and a tote.

Yep, that silliness is finally gone. And if you don't check a bag, you won't have to worry about the automated baggage crushing and mis-routing system at Terminal 5. The clueless, nasty BA ground staff are still there, however