I ordered these from ZDecals. I vacuumed and scrubbed the carpet to remove any loose material then followed their instructions. Time will tell if they stick. The ones from Vinyl Images inc that have been on my boat since I got it have withstood the test of time without issue.
This is the FAQ for the carpet graphics.
https://zdecals.com/pages/faq
13 What's the difference between a carpet graphic and a vinyl decal?
Carpet graphics are made with a special adhesive and non-skid coating, specifically to stick to carpet and be walked on. Vinyl decals will only stick to smooth hard surfaces and are not designed to be walked on.