Griz - I was in USA with Continental last week - there was a mix of regulations and checks, but over the two t/a flights and two connections there was nothing consistent.
Coming through Dublin there was the usual 'Step back from the line, Sir' reception at check-in. Going through x-ray into departures there was no special US treatment. Going through the US Imigration section there was no special treatment, no extra scans, nothing. Before getting on the plane (in the airbridge) there was a quick manual bag scan, but not entirely thorough. The only scans for liquids, etc . . . were done by airline staff, not US officials.
Connecting through Newark there was only the usual scan, but they did make sure to point out that liquids weren't allowed. Didn't seem to put the guy in front of me off drinking from his bottle as he approached the check.
On both flights there were people happily swigging from bottles - probably bought from the airside shops.
z