Re: Fudging ETA's in procedural airspace.
Never encountered this when I worked in that part of the world, Scottish with their radar did a good job of determining the correct order and issuing releases to us as appropriate.
The trick I came across was the operator, that, when realising they would not be number one, would just pitch up at the MSA with a freecall. This could be at the best irritating and at worst damn right dangerous if you already had two or three in the hold/on the procedure. They would either be told to join VFR or essential traffic info would be issued and the a/c instructed to hold in a position at least five minutes flying time from the hold (not ideal in Class G airspace). Despite this, they would persist in trying it on.