That is not 100% accurate. I was in hospital for a long time and one day a woman, I have no idea about the department she worked for in the hospital, came up to my hospital bed and said, "we see you are on a long stay visa" , she even told me the exact expiry date, and asked if I would a document from the hospital regarding the 90 day reporting. But because I was being discharged the following day, I said no worries and will do it myself as I was still in the allowed 7 days grace period.
So yes they check. But YMMV
Edit: Forgot to add, On admission day, they took a copy of my passport which I had to sign