Indeed. When the historic vehicle rules were introduced they forgot to update some piece of legislation, and the date by which vehicles can wear the old plates rolled with it up to 1979 or 80 before the regs were tweaked and it was stopped.
Being an old timer they just look wrong to me on anything later than a '72. Seeing g T reg escorts wearing them sets my teeth on edge.
Certainly if I'd caught a 2002 bike back in my day wearing one it would have been going to the pound unless the rider could produce either a correct plate or a trailer to cart it away on then and there. Sometimes folk would lie and claim some nonsense that it was IoM registered, or whatever, and we'd knock 'em off for trying to pervert the course of justice as well (although unless it was an extreme attempt to avoid prosecution the CPS would usually reduce it to Obstruct Police.)
And besause theyre not 'roadworthy' like that (ie, mechanically safe and compliant with all prevailing legislation) insurers use it as an excuse to give owners the bird in the event of an expemsive claim.
Also the manufacturer of the plate risks prosecution as well - there is no legal "show plates" defence like some wideboys try and claim in their ads.
There are a lot of downsides and no real upside to having a non complaint plate.
But, as mentioned above, nothing wrong with having such a plate for decorative purposes on a bike thats not on a road.
Anyway, enjoy the free bump and GLWS.