Have you ever been going through Irish Airport security and suddenly an alarm goes off. You think to yourself, why does this always happen to me, and I'm not even carrying any weapons of mass destruction ?
Well you may not be even carrying something as small as a nail file but you have been randomly selected for a body search, whether you like it or not, I suppose it depends on who's doing the searching.
The machine that has the built in alarm is programmed by the operators, in this case Dublin Airport to select every fifth or sixth or whatever number they choose to be searched. So now you know that it's nothing personal and it's not like they didn't like the look of you.