The students don't know it's illegal? The staffs also don't know? No enforcement really no impact even if law states it's illegal..
Many years ago declared illegal liao.
All thanks to the anti-MSM siaolangs who switched to alternative media chock full of crazed goons playing journalists back then. U now got all these vapers who "don't know" about vapes being illegal for more than 10yrs liao.
That's the problem for the last few years, where vape is just a fine. Now things are changing. Vaping is a serious offence. Hopefully things turn for the better, from now on. Some students vape becuase of stress and peer pressure. Smart people not automatically are sound minded. Mnay smart people do silly stuff, that even an average joe was wondering , why they are ruining their life.
Everyone knows you are not supposed to vape.
But everyone also knows it is hardly enforced.
It’s just like PMA, everyone knows PMAs are meant for the disabled, but everyone also knows this is not enforced … end up you have
abang posing for photo for a
news article with his children - plural - all sitting on their PMA together, and
abang talking about how it adds convenience to their lives to use it to send his kids to school and $#!t.
Catching vap
ists (yes, a person who vapes is called a
“vapist”, because a person who rapes is not called a
“raper” 
) is not strictly enforced, until you go to any prata joint that serves late night supper crowds, you will find vapes openly placed on the table or even people openly vaping at their table.
In Singapore, the only way to make everyone do something (or not do something), is to apply enforcement. Anything that does not come with enforcement - even if it is law - is just a
suggestion or
recommendation.