The "spray on" fabric paint was used on the carpet in my car before I got it. It will wear away where it gets stepped on, so under the pedals, under the glove box if you have passengers regularly, and the same thing for the back seat, where people step on the floorboard to get to the back.
It also looked like crap, or atleast the previous owner did a terrible job. The tips of the strands of fabric on the carpet had droplets of dry paint, like they tried to do a heavy coat and it overloaded the strands. I had to scrub it away before I dyed it.
Jim, did you dye the peice of clothing correctly? Theres a certain way to do it, you dont just pour the dye into a bowl and dip everything in. Theres a write up on another site about dying carpet, I think it was made by the member "Ishibog" or "Ishbog" on team integra. Look in the Appearance forum in the articles on right of the page, it should be there. You need a large trash bucket, like 32 gallons or something, 6 bottles of RIT dye, 2 canisters of salt, and lots of hot water. May be more work than your looking to do, it will take a few days to complete the process. Dyeing for 2 days (Or more), then spraying it down until the water youre spraying on it runs clear, then letting it dry for another day, at least.