yeah, depends on the x-ray operator mostly. We used to get stopped and bags opened
every time going through Denver 6-8 yrs ago. They acted like we were terrorists - even our 12 yr old daughter.
Recent years have been completely different. They ask "scuba gear?" as soon as it goes in the machine. Yes, scuba regulators and computers in this bag, camera gear in this bag. They smile and wave us through.
One time recently the x-ray lady was very nice and asked if we minded opening the bag to show them what it really looked like... she called over a group of other TSA agents and they "oooh aaaahh.... now I understand!" when we showed them the regulators, etc. You have to remember, they see pictures of what bombs and weapons look like in an x-ray machine so it helps when they see a bunch of funky wires and pieces and what it really is when a bag is opened!.
we pack in one bag - both our reg sets, masks, dive logs
in other bag - camera, camcorder, batteries, chargers
in personal bag/backpack - laptop