If someone just wants a visa, then it's much easier to get a quick and easy masters instead of doing a PhD with 5 years of research.
You can master-out in the middle of a PhD program, which is frowned upon, but it is difficult to get funding if you directly apply for a masters degree.
Perhaps the solution is to decrease the negative cultural backlash against predisposed intention of leaving with a masters despite applying for a PhD, which is currently seen as some sort of betrayal of the adviser if you are going to have your grad students do boring work. It'll be a win-win deal in that case.
When I was in school, one applied to "MS/PhD" programs most typically. And all imaginable variants existed in terms of funding and likelihood of leaving with only a MS. Some schools would fund no one till they finish the MS stage, and others would fund everyone from the beginning (just give every accepted student a full fellowship for the first couple years). And also some schools were pretty notorious for kicking people out at the end of the MS stage, with a difficult exam at this step or not enough advisors to take them on for the PhD.
One positive side, though, is if you wash out of a PhD program at any later stage, you at least walked away with a Master's.