no, i WAS 100% certain that it wasn't as simple as you said. you cannot gain such permission from immigration when doing private tuition, which was one of the possibilities you listed. you also seemed to think that what you proposed was not a problem at all. when, in fact, there IS a problem. what you proposed is NOT LEGAL UNLESS YOU HAVE PERMISSION from immig, which is not always a simple thing to get.
perhaps, instead of being a pinhead about it, you should have ASKED how can i make this happen instead of assuming that what you had proposed was not a problem?