Technically, no you couldn't. Realistically, Levi-Strauss isn't in a position to patrol every garage sale. Rolex, however, hires investigators to find out where those fake Rolex's on the streets of NYC come from, and confiscate them.

To compare the sale of one of these chips to sellign fake Levis at a garage sale depends on who's selling. If I had one, and unloaded it to a friend visiting my house, I'd be beneath the NFL's radar (still technically breaking the law, however). If a chip dealer advertises them on his site, he is obviously a retailer dealing in knwon counterfeits -- and should expect a cease-and-desist. I wouldn't expect the NFL to have people patrolling the convention to find anyone with one of these chips in their collection. IF their panties are in enough of a bunch over the issue, however, it wouldn't be unusual to have them send a trademark invesitgator to make sure dealers aren't offering them in bulk.

If someone sells it through eBay, it's much more likely that eBay will get the cease-and-desist.