Quibble about specific definitions all you want, it's still an exploit.
Yes it is. A rather unfun but totally legal one (and from the sound of it, a hail mary, 'OMG how am I going to deal with this list' play that he lucked out on paying off), the merits of which have been, can and will be discussed ad nauseum in this and many other threads. It is NOT, however, and infinite loop as you asserted earlier.
Edited by Forgottenlore
I thought there was something in the rules about "infinite loop" or something like that. Wouldn't fortressing be consider an infinite loop?
There is such a line, but I believe it relates to pilot abilities/upgrade cards, and unfortunately not to movement. Because you're right, this is potentially an infinite loop exploit.