That's twisting the story quite a bit. Compuserve made GIFs (unaware of the patent) and Unisys had been charging companies for the patent for a long time (but were unaware of GIF). When Unisys found out, they started charging. It was hardly bait and switch. At no point did Unisys ever tell people to use GIF because they had no plans to charge for it.
"Unisys does not require licensing, or fees to be paid, for non-commercial, non-profit GIF-based applications, including those for use on the on-line services.
Concerning developers of software for the Internet network, the same principle applies. Unisys will not pursue previous inadvertent infringement by developers producing versions of software products for the Internet prior to 1995. The company does not require licensing, or fees to be paid for non-commercial, non-profit offerings on the Internet, including "Freeware"."
Unisys has frequently been asked whether a Unisys license is required in order to use LZW software obtained by downloading from the Internet or from other sources. The answer is simple. In all cases, a written license agreement or statement signed by an authorized Unisys representative is required from Unisys for all use, sale or distribution of any software (including so-called "freeware") and/or hardware providing LZW conversion capability (for example, downloaded software used for creating/displaying GIF images).