Currently me and  a friend have a ongoing banned member list,that continues to grow. There are a couple of members on here that either sucked as a buyer,or as a seller,or both. There are a couple listed because of excessive profiteering off gamers too,but you will have to make  a personal judgment on wether you would want to deal with that type of person or not,or any of these people,but either way,this would be a great spot to place bad member ids.
The list:
 jcaleiras (currently purposefully selling a non working MVS Rage of the Dragons MVS cart,listing he has no way to test it so its as is,even though he has a consolized 1-slot and many MVS carts. His response to being busted was "Buy at your own risk".)
 Cephalgy
 johnjohn5274
 2800yen
 2many_collectibles
 3secsnipe
 aorian_star
  arienzo1
 banger98
 bear_pawjeff
 benchards
 big-b-toys
 bjomama
 bluebell1917
 bozzspring77
 br1574
 cdad54
compstuff58
czsoccer
 ddav44
dragsy
dsaucierjr20
 endless201
 flammie_634
 frostadue
 fura-philomina
greatcompany026
 guingo
ironcross895
 itchybon
jmkurtz
 kingdragonzero
 leonardo160714
 lolanglenn
lrb7962 
marine_2k4
 mellissalaserdisc
 mustangclassics5
 neotropolis
 oldcompcollector2003
 ovenman6677
 peyton_anthony69
 poeticjedigamer
saturn09
starlitegaming
shaka818
sidtx17
sl_dickens 
spacescorpion79
 thebigd80
 tink-a-link
 usrpguk
 whiteyflyer 
 wildecoyote1966
 ThsGrlLvsThtGirl@aol.com
 e.cook@fuse.net
 16-bit
 Shooters49ers
 squirrleyguy
 x-vision-x
 invideo2002
Fixing to be added to this list are shooters49ers for a item not received and no response to claim filed in paypal, and discountgames for a similar situation. They did not included in the package everything I had paid for,and they sent me damaged goods also including carts with badly damaged labels,excessive rental stickers,and a cart that was melted and warped on the back casing. This type of stuff was not listed in the details. Discountgames did send  a check for a slight refund,but I do not accept personal checks of any type when its ebay involved,checks from unreliable members tend to bounce,and they have not to this day responded back to the dispute/claim opened on paypal. 

I did the above to their check and mailed it back to them. They tried to refund me outside of paypal hoping I would drop the claim so it wouldn't go on record. Note they didn't even make the check out to the right person involved. They made it out to my girlfriend,who is listed on the second address on my paypal account.
Update: After digging further into things on Discountgames  I found that they receive over  a 100 negatives a month,but they usually get unnoticed by the percentage system because the seller sells over 15000 items a month. About every negative left has been for not receiving a item,or getting wrong item or something. Discountgames always leaves  a generic negative feedback in response,even though the buyer is not at fault,only the seller. Basically Bullseye on a mass scale,but with semi-lower prices on some items. Its too bad because they do have a nice selection of games with what would be fair prices if not for the fact of all the problems involved.