In the USA they already do a kind of profiling. Just been on half a dozen flights there last week and got stopped / extra check at gate several times. It isn't all random. One of the airline gate staff explained that certain factors generate a trigger for an extra check. They have a list of those people down for this at the gate.
Mind you, the new TSA security guys are WAY better than the previous goons. Polite but thorough. And they are efficient / have enough staff to do the job properly. Didn't have to wait more than five minutes at any of the airports I went to. Plus their training seems to be consistent across all airports.
CS