I have... many times actually. Every time I go through a metal detector or have my bag searched (nearly daily), the people are usually pretty friendly. It probably has something to do with me not having anything to hide, not being grumpy about it, and being friendly to the person. I found that their attitude correlates to your own... so if you want to be bullied, give them grief. If you want them to be friendly, be friendly to them. Same goes with any public facing employee: bank tellers, DMV employees, etc. The problem is the policy they have to enforce. They are human just like you and probably know the policy they have to enforce is backwards. No need to exasperate the situation by giving them crap for doing their job.