I don't know about riddled, and personally I have never had a problem with anything I bought on eBay, but some things you will find, and which have been discussed here in the past are..

misrepresenting chips as from a casino, when they are fantasy chips sold by the Mfg. for home play or made as collectibles.

Excessive shipping charges. (read carefully)

Calling common chips obsolete or rare.

Making home made chips and not being up front that they are just blanks or other chips with labels stuck on them.

Listing large lots of chips, all fantasy chips, as $xx,xxx.xx face value casino chips, when you could buy them all for 39c each from Paulson.

That sort of stuff. ;-)

As for possible problems anywhere on the internet at any auction site, taking money and not shipping is sometimes a problem. Selling stolen goods. In the past, most of these people have been tracked down by the Feds. and jailed.