LnS, in extreme circumstances it's possible but is a good example of when I would not be in the slightest bit surprised if the pilot totally ignored the controller. It's a very similar case to cancelling a take-off clearance when an aircraft has started to roll - a couple of years ago I recall seeing some guidance from the CAA to help controllers when faced with circumstances where they might feel the need to do this.
The problem is that cancelling a take-off clearance after the aircraft rolls, as is often the case when instructing an aircraft to go-around, there is very little time available to make the decision and transmit the instruction. An ideal might be for the controller to explain the problem to the pilot (giving both a better underdstanding of the situation) and agreeing a course of action. In the real world, of course, all this has to happen in a split second and so the controller should assess the risks and do the best thing that their professional judgement determines.
The vast majority of the time all of the things we are talking about on this thread are done efficiently and safely by the pilots and controllers involved. Unfortunately we only tend to debate it on the relatively rare occasion when it doesn't go well. If I recall correctly the guidance on cancelling take-off clearances was issued because, despite years of sensible use of the procedure where appropriate, a couple of controllers made poor judgement calls within a matter of weeks.
172driver, I'm always civilised - if slightly tongue in cheek at times. I'm not famiar with the detailed FAA rules (hence my offer to debate UK or ICAO rules only) but I believe they are very close to the ICAO SARPs. However I would offer the following thoughts - and maybe an FAA controller may care to comment or correct me. An aircraft can be given an anticiapted landing clearance if, amongst other conditions, there is a reasonable assurance that the runway will be clear by the time the aircraft gets to the threshold. As with any clearance, if circumstances change and the clearance is no longer valid then the controller will cancel or amend it. An anticipated landing clearance is still a landing clearance and if for some reason the controller no longer has assurance that the runway will be clear when the aircraft gets there, I would expect the clearance to be cancelled.
In essence any clearance is valid until it's 'used up', cancelled or amended.
As to the situation in the post you refer to, it's impossible to comment without more details but as I mentioned in an earlier post, good practise would suggest that the pilot should be told why he or she is being sent around simply to avoid the pilot feeling the way he/she obviously does to have made the post.