NFRs typically refer to the retail channel, and do not typically apply to end-users. How about some examples...
Movie Preview releases... versions of movies on VHS or DVD (or BD I guess) that are sent to the media, video stores, etc. These are sent to the company as per an agreement with the movie company. These items are either to be kept or to be returned after being finished with it. If you watch one of these movies, it will pop up every 10 minutes or so saying to return the movie to the manufacturer.
NFR versions of software (Windows) are gift copies that are sent to companies. That company is not allowed to resell the product but can only give them as gifts to individuals. The individuals can do with what they please, but current release product can be pulled from sale if they were to be put on Ebay or Amazon. For example, you couldn't get away with selling an NFR of Windows 8 but XP would be fine.
NFR games (say Sonic the Hedgehog in the Genesis) were marked as such so that the retailers couldn't remove or substitute the cartridge and offer it for sale on its own. Once the product enters the secondary market, it can be sold as normal.
There are products, however, that are not allowed to be resold under any circumstances. Primary example of this is anything marked Intel Confidential (CPUs primarily) or engineering samples. Resale of these products are illegal (at least in the US) and must be returned to the manufacturer to be destroyed or recycled.