Impossible to be a scam since we're happy to use escrow.
It's worth pointing out that there is a common scam where people offer two services: one is trust-free and can't be a scam, and the other requires trust. They use the legitimacy of the first in order to convince people to use the second, and then run off with the second group's money.
I'm not saying that's what you're doing here, but it makes me nervous that you aren't defaulting to escrow in all cases.
Thanks for your input. We would be happy to use escrow in all cases, but also saw lots of demand from people who wanted to move their coins around. We do address this concern in our FAQ for people who choose not to use escrow.