So far
per mjjluver:
Tillandsia Velutina -- devoured
T. Pseudobaileyi - okay
My experiment, i mostly pick the big ones in my collection so hopefully even when there are damage, it can recover easily:
okay
T. Baileyi Mexican/True
I left it in the tank for 5 days. Watermelon mostly used it as a climbing toy, once he carefully took the plant out of its shell so he could check out the shell! only on the 5th day it started nibbling on one of the leaf for a while. I took it out since the plant is not huge yet, i don't want to take too much risk. but I have a feeling crab (at least watermelon) doesn't care much for its taste.
Watermelon carefully taking T. Baileyi out of its shell...
I've now put in my own T. Pseudobaileyi, it has been one night, no damage whatsoever.
shredded:
T. Duratii - left in the tank for 2 days and 2 nights, partially shredded, luckily i have a huge Duratii and only little watermelon is active in the tank so the damage is recoverable.
Here are the damaged areas of the poor duratii. I've had it for a couple of years, and recently it started to lose its shin on the leaves, so i thought maybe popping it to a high humidity place will help. then i did some research and realized it seemed to be the only Tillandsia that could survive the ourdoors in Arizona! So i took it out of the crabitat and put it in a sunnier spot. will see what happens.
T. latifolia - left in the tank for one day and one night, started been shredded from the bottom (dry leaves first). i took it out to avoid further damage since i'm rather fond of it.

a few leaves (mostly dry) on the bottom of the latifolia received the crab shredder treatment (on the right side of the photo) after one night in the tat.
Next will try
- bulbosa
- caput-medusae? maybe, i suspect it will get shredded. Mine bloomed a few months back and is putting out a pup. I would like to wait for the pup to grow bigger before putting the whole mom-pup cluster in for a test.