Yeah it's there job and blah blah blah. Still doesn't excuse the rudness of the majority of them.
They may have the right to go through your bag without asking, but make it feel like a choice. Be courtious and polite like we are expected to be.
"Is this your bag sir? Do you mind if I open it? It looks like you may have 'x' that needs to be screened serperatly."
You catch more bees with honey............