It's the same case with normal trades, even people who are going first get vouched after the trade. - Whilst they haven't been trusted with anything either, they have shown that they are not out to scam.
You're vouching that the trade went through and that both are legitimate sellers which none of them tried to scam during the trade. I personally think it's fine.
The only person who should be vouched after a middleman service is the middleman. The middleman is, after all, the only person to have been trusted with anything.
I sort of disagree. I think that if they MM legitly, they deserve the vouches. And when you said "After they get 3-4 trades in, they've got nearly 10 vouches from half of that amount of trades, then they pressure a newcomer into going first because they have "More vouches" and scams occur here, the new user gets angry and may result to scamming later." But seriously, who would use an MM with 10 vouches anyway or even go first to one? Even a newcomer should know this. But I disagree on how the MM vouches the other people of the trade as they have nothing to have trust on.
No support...it should be totally up to the MM. If he deems someone he is mm'ing for trustworthy, why can't he vouch for them?
The only person who should be vouched after a middleman service is the middleman. The middleman is, after all, the only person to have been trusted with anything.
....I don't support. If your using a Middleman that slightly means that deserve a vouch. If you don't use a Middleman, you usually are a scammer.

