I've tried it and had 4 of 6 cats toilet trained. We were very careful with the training pan and worked the system very carefully. Even though we never had a problem when we were home or awake, I hadn't quite gotten out of the habit of leaving the training pan out of the toilet. I was always afraid one of the cats (he was on the clumsy side) would accidentally fall in, so I would put the training pan in.

Then one night I was very sick with a horrific migraine and had forgotten to take the training pan out before I made an emergency run to the bathroom. After that, none of them would use it anymore. Even got another pan and tried... no luck. Guess I ruined their fun.

My only complaint with the whole system had to do with the fact that I had a padded toilet seat and they liked clawing it. Have you ever sat on a cat clawed, padded toilet seat?? "Odd" doesn't begin to describe it.

If two of the three cats we have now didn't weigh over 12 lbs., we'd give it another try. I'm hoping someone makes a plus-sized training set.

Having them toilet trained shouldn't mean taking away the litter box. Unless you're absolutely certain it won't be used, it never hurts to keep a spare just in case the bathroom doors get closed and the cat can't get to the toilet (helpful tip from friend who talked me into trying to potty train my cats).