There have been a few accounts that have stated toons on other Emu servers in the listing and have had no repercussions. Aslong as your selling point is the p99 toons and thats what your valuing the account off of it should be a issue i wouldnt think. Darian's account that was for sale listed its other server toons at the bottom and was posted for months.
Ref to Darian account sale thread
http://www.project1999.org/forums/sh...ghlight=darian