Before you do your jboots MQ, if you give hasten 4 unstacked items that are not a part of the jboots quest, such as 4 unstacked water flasks or rations, it will "reset" his MQ inventory which will prevent older turnins from causing your jboots MQs to fail.

I have read on the forums that this is confirmed not to work with velious armor quest MQs. Are you sure it works with jboots (or any other MQ)?

I heard this worked for jboots but i didn't properly test it.

No item no plat. Seller really should assume risk. The pay half thing seems rubbish.

This is the way I see it as well.. You're buying the item.. Seller chooses to be involved in the risky business of selling MQ's.. The risk is his, it's his business.. Not yours.

As a common seller of MQs I tend to trust a buyer if the character is high level and / or from an established guild, even if the item is going to an alt. I’m always clear on the instructions have the buyer trigger responses where applicable or verify faction where relevant. Happy to say I’ve not had a failed MQ yet but in the case where it’s previous turn in to blame I would eat the loss and move on.

When the buyer is low level I ask for payment in advance, but would refund if it’s clear the failure was due to previous turn in.

Basically if you are selling, you should be informed on all the factors of the quest and prepare the buyer. If the MQ fails due to outside circumstances I would assume the seller takes the risk.

There is no etiquette, if for no other reason than the the staff will not reimburse and hence doesn't endorse MQing. Logically, whoever is assuming the risk should be getting a better deal if successful, but it's all up to you to suss out.

I was and am fully aware of the staff policy on MQ's. What I meant by "etiquette" in my OP was what is the commonly folllowed procedure in MQ trades by players on the server. As in, if I demand payment up front when selling an MQ is that going to be frowned upon? Or if buying, and I demand to only pay once the MQ is complete, likewise?

And like i said, there isn't any and gave you the reason. There are way too many variables to consider for a standard of etiquette to be adopted when there is zero chance of failed turn-ins being reimbursed.