Same thing on my server. I ended up buying it because whats the worst that could happen? Blizz takes my 26k (i haggled down) and takes the mount away. So i bought it.
Immediately after buying it, the same dude started shouting to sell another one. This was 4 weeks ago and there are still people shouting to sell it for 28k, sometimes the same, sometimes different. All level 1 toons.
But i still have my Jeweled onyx and have never been warned or banned or anything for it.
So i dunno whats up but i'm happy.
It's worth ~30k any way and loads of people have level 1 alts for selling stuff (including me).