MQ questions

[Wiff]

I have plenty of experience with MQs just not when a transaction is involved.

I've heard all the horror stories of MQs gone wrong, and I'm familiar with the staff's policy, so I've largely kept out of the MQ market. However, quite a bit of odds and ends have gathered dust in the bank: minor epic pieces, crappy Thurg armor (Velious leather gloves are my curse), VP medallions, etc. Plus I've been looking at some Skyshrine stuff for alts.

Who is generally expected to go first, the buyer or the seller? Do you typically pay/ask payment upfront or handle payment after a successful turn in?

Is there any element of GM assistance at all if things go south? If a player takes the money and immediately /q's out, would that be treated as a MQ gone awry or would they reimburse? Would they give information on why a turn in failed such as insufficient faction or an incorrect item, or does the seller typically eat the loss?