I've done the same in the past during char transfers. Never got moaned about though. But then again, on arrival I intentionally didn't flood the market.

I'd say be patient, putting 10 or so max of any high level mat on at once for 2 reasons:

1) So to avoid this abuse
2) To not distort the market, (if you have 50 primal mooncloth all on at the same price, it forces others to undercut you and yours will not sell).

So just be patient, you dont need all the cash NOW! Put it on at average prices and wait for it to sell and you'll make 20% or so more anyway.