I don't know if I would classify it as "forbidding a pilot to land", but there are plenty of situations when a landing clearance cannot be given eg another a/c occupying the runway, or debris etc. on the R/W. These are operational situations when it would be impossible to clear an a/c to land - because it simply is NOT clear to land. in these situations specific go around instructions will be issued. In non operational situations, an authorised person will be required to instruct the a/c that landing clearance is refused.