Yes, it is a lazy way of stopping requests. I also modified Iridium's "trk" scheme code to pick up domains ending in qjz9zk so I can notify the user.
- doubleclick([A-Za-z\-]*)\.net#60u613cl1c4\1.qjz9zk
+ doubleclick([A-Za-z\-]*)\.net#doubleclick\1.g.invalid
https://en.wikipedia.org/wiki/.invalid