Below is a post by a carpet cleaning technician on my carpet cleaners' forum...
A customer called today to say that she bought a small rug from IKEA ,and the rug has transfered red dye onto her carpet. I have had a look and sure enough the dye has transfered to the nylon cream carpet. I have done some testing to see if i could remove it with the usual encap spotter/solvents etc but to no avail any ideas other the dye stripper?
He later said that he was told they were small cheap rugs they are selling by the check-out. Customer placed it at the foot of her bed, and now has an expensive? problem!
Just a word of warning about this scenario, as it isn't uncommon. Its called CROCKING (dye transfer from one surface to another). Other common ones we encounter are dark brown or black microsuede lounges crocking onto clothing, new blue jeans crocking onto light coloured lounges, etc, etc.
It pays to think & check before putting cheap rugs down.