Late landing clearances are often the result of the preceding aircraft having a long taxi to vacate the runway. Here a 'land after' clearance from ATC can be very useful, where the onus for separation falls very firmly on the shoulders of the following aircraft. ATC seem to use this clearance infrequently at GA airfields. On a couple of occasions, I have transmitted on short final. 'G-XXXX can accept land after.' the response has been a land after clearance, a safe landing with adequate separation, and avoiding a go-around. However, land after can only be given in certain conditions (daylight, good vis, clear visual contact between the a/c etc).
This does not apply to the CIM scenario, I know, but is relevant to the general subject of late landing clearances.