I was trying for overlapping flights to trigger a "red banner" for future use thanks to storms and dense fog. But I could not afford to lose the original booked flight on the same day or I'd be stranded for days. So I was a chicken and gave up.
I know A-B-A same day works fine as long as there is no overlap. But you cannot have two flights that have either the same origin or same destination on the same calendar day. So A-B-A-B-A is subject to cancel bot according to the current CoC. Can't have two trips of A-B and the other another A-B or A-C same day either.
you can do A-B C-A on the same day if there is space between them
you can’t do A-B in am and A-B in pm
you can do A-B evening then book the same A-B next day am
but you can do A-B and C-D on consecutive days
i do think booking flights also matter. Employer booking may have different rules n double bookings or situations like a bunch of back and forth because if a business books it it could be some sort of courier service needs