I have a question regarding the secondary screening procedures. The other day I was going from SFO domestic to the international section, and passed thru the security there. I took my laptop out, had nothing in my pockets etc. I had sneakers on. I put everything on the conveyor and stepped thru the m.detector. No beep. I was then asked to sit on the chair and my shoes were run over with the wand. Then I had to stand on the feet markings and I was wanded. Two dangerous rivets and a button fly were discovered on my 501's. I was then released to watch my laptop get swabbed. What I would like to know is why did I get secondary search when I had already passed thru the frikken detector without setting it off? Is there a procedure for this unbelievable waste of resources? Tho I guess with probably 20 TSA agents and just me going thru one side they wanted to do something useful.