I understand that Jeremy has volunteered to do a test trip to the U.S.A. this month.
If and when he gets back, perhaps he will write up his experiences for LuLa.
OK: my experience. I travelled with a 5Ds in a ThinkTank roller case with three lenses and assorted cables, card reader and so on. Out on 20/8, back on 26/8. Boston's Logan is listed as one of the places at which the enhanced measures have already been implemented. I'm not in the TSA-Pre programme (although the global entry programme does look very interesting, given the length of the queues: it was only some answers to the guard tinged with
suppressio veri that got us through Logan in 40 minutes).
Outbound from Heathrow to Logan: standard search. Laptop and iPad in separate trays, camera bag passed through unopened. Shoes on feet, belt off. No difficulty and no different from any other trip from the UK to anywhere.
Inbound from Logan to Heathrow: pretty much the same. This time the Kindle had to be in a separate tray, as had my shoes but not my belt (so my trousers didn't fall down again, which was a relief). I was asked if the camera case contained any liquids (no) or "electronic devices larger than an iPhone"; I said it had a camera, the guard said fine and it went through unopened. Again, no different from usual.
From this extensive and carefully-controlled study, it would appear to be a storm in a teacup.
Jeremy