It's quite a dumb trick. There so many complicated tricks for such simple tasks. I considered making a level were people can start from to do complicated things. Here's what I have so far.
Testing the level will bring up the Lakitu NPC tab.
Sections 4 & 2 have a sample instant Mario-only filter. Player 2 start location is in section 4 and section two is the midpoint version of that filter.
~~~Septentrion Signature Space~~~