While it's amusing to have mind spiders spawn when one is a good hundred blocks above the ground, it seems broken as far as balance goes.

I propose putting an event pause in place so that if a warp event would occur while airborne, it's instead triggered the second one lands.

Is your concern about the spiders just being goofy and instantly falling to their deaths, or are they able to hurt the player? Thaumcraft warp events are very inflexible, so unless it is a major issue it will probably have to wait for the next content update, where I was planning on making warp more flexible anyway.

More the former, it takes the danger out of warp events. Understandable though if there's not an easy fix