Adherence to the 80 hour rules depend a lot on the attitude of the faculty. Many programs take the "we always work it out, wink wink" approach. I have spoken to residents from several different programs at various conferences and know that some places , off the record of course, the residents come no where close to fitting under 80 hours but document that they do (like an earlier post said, who wants to get their program discredited before they graduate?). There are however programs, like mine, whose chairman are very anal about the whole thing and dont want to run the chance of getting caught cheating.
Another thing to note is that at programs that have home call, if you go home for any time at all, the 24 hour plus 6 to finish things up rule resets. Apparently there is the possibility of changing the rule to say that if you are there for more than six hours after the "end of the normal work day" (up for interpretation) then the home call person is treated like a in house call person and has to go home at noon (assuming you worked 6am-6am)
Bottom line is that unfortunatly it is tough as a med student interviewing for residency to know a programs true utilization of the rules.
Trivia for you. Who are most work hour violations filed by? Not residents, but teir spouses!