It's possible to get trich from a hot tub, if the hot tub isn't cleaned, and maybe a toilet seat (there is some debate about that, and I'm not sure I believe it, or we'd all have it).
Is there a reason you are asking?
Well. Trichomoniasis cannot be spread through toilet seats. Just think, if it does spread every tourist will be affected. So, what you have heard was wrong.
And, I am 100% sure, that trichomoniasis spread only through sexual contact.