Well, you can "force" it, but the result is not what you'd call broadcast quality. If you compare the shells of a beta SP and a regular betacam casssette, you should find an extra hole in the SP casing that tells a sensing switch in the deck what flavor of tape it is. Occasionally the switch goes bad, and lets you record using the wrong tape if you put that in, but the recording is not clean.
I remember a long time ago now, there was this guy on another forum, wrote a LONG post about how clever and proud he was in coming up with a way to "beat the system" at his university AV department. They were running S-VHS decks, and his rant was that they couldn't afford the more expensive S-VHS tapes. He insisted the tapes had no real quality difference, that this was all marketing hype, and that he was going to "beat the system".
He deterimined it was the same kind of indexing hole issue that allowed the machine to detect s-vhs or regular tape. So, he goes into this long spiel about buying a little drill press and making a special indexing jig for it, then drilling his own holes int he bottom of case after case of tape, one tape at a time, all the time using a shop vac to keep grains of the drilled plastic out of the cassettes, etc etc. And he was bragging about all the money he saved (but not all the time he wasted). Triumphantly, he said the tapes now ercord s-vhs, and he's apyin a whole dollar less per cassette(minus the labor).
So one guy responds to this long post: "Why didn't you just take the lid off the VCR, reach in and unplug or short the little sensing switch to disable that, instead of adapting every tape that goes in?"
The guy with the drill and all NEVER posted again. Too mortified, I guess:-)