It’s 24 hours before aggression can start, and NPC corps can’t be wardecced at all.
How are you going to actually do anything useful with this approach?
Oh the fail. You can’t pipebomb the mach.
Pipebombing relies on knowing exactly where the target will land out of warp.
Bump machs are constantly moving. You won’t be successful with smart bombs.
Just gank the mach normally. It will be cheaper and more reliable.