From my experience, if they do what you are requesting, a lot of times they won't be able to do a bait and switch on you.
Some of them could be scams, but if you hold their "real" picture then it is harder for them, plus they may be concerned that you are LE, but it is doubtful.
From my experience, it just easier to tell them to meet you at a hotel lobby and pay in cash. But remind them that if you don't like them, you ain't paying for nothing