They did offer people who bought new computers with the later version of Vista a chance to upgrade to Windows 7 for free. That's the only other time I heard about it.
i did take advantage of the Windows 10 upgrade from 8,1 after thinking about it for a while and have had no problems related to changing But like most of us I use a dedicated browser only for WGT (Maxthon3) and have it set up to clear history on exit. i also clear caches frequently (about every 9 holes or so). So far that seems to work.
However, past performance is no guarantee of current outcome, and your mileage may vary.
phred952