Some of them are apparently getting 2 month extensions in their passport, possibly covid extensions, although I don't know what the rule is. If they are in Thailand legally, it makes sense to try to get whatever vaccine they can get, as there is no downside risk. If there illegally, perhaps there is some risk in showing up and presenting a passport.
Having said that, even with no vaccine, many of these lads will be at less risk than some of us with a vaccine.