I was flying out of SFO and there was no line at all. I walked right up and was asked to take off my shoes. I explained that I fly regularly and that these shows are ok. The TSA agent replied "I highly encourage you to take off your shoes". I didn't bother. I walk through, no beep, I gave him a little look like 'I told you so' and then he asks me to step to the side for secondary screening.

So I asked the secondary TSA agent why he didn't just tell me that I would be wanded later and the second rep told me that they're not allowed to tell people what will happen if you don't take off your shoes and they're not allowed to tell people that they must take off their shoes.

Who writes these rules?