Every time I think of a weird scenario I can't get it out of my head until I show you guys.
A Corsair Eldar player is playing against a Chaos fleet, using the 2010 update. One lone escort is all that remains of a squadron. The Chaos player has had enough and wants that escort dead. Sadly, the only guns in range are lances, and some bombers are also close enough. Over the course of the turn the Eldar escort makes 30 total holofield saves with no failures. Before the Chaos player flips the table, how do the blast markers get placed?
Blast markers get placed in base contact with the Eldar ship, so the first 6-8 can fit around the base. Let's say there are 22 blast markers left.
1. Blast markers are placed in base contact. Even though you are not supposed to overlap, the base contact requirement supercedes that and you end up with a ring-shaped jenga tower of blast markers.
2. Because blast markers are not supposed to overlap, simply place each new marker touching one of the blast markers touching the base, until you have created a 2nd ring. If this ring is full, keep going until you have a 3rd ring and so on.
3. The space around the escort is already full of blast markers, and since blast markers aren't supposed to be placed on top of one another, the excess markers are simply not placed, to prevent board clutter.
I say #1 is most closely supported by the rules, but a precarious jenga tower of markers seems inconvenient. #3 is the easiest and makes it so the board is not littered with blast markers. However, the Chaos player may make the argument that it should be littered! After all, he doesn't potentially take damage from flying through them.