You'd need a programmable remote, but I don't think you'd want to risk a guest walking out with or damaging a $50-$100 remote.
They don't make TVs or standalone devices that when turned on tune to a specific channel. Cable boxes can do it.
I understand wanting to tune to a welcome channel, but I don't think you have an easy solution. Honestly, I'd just put up a placard saying "Tune to channel X for such-and-such hotel's welcome program for information on this and that!" Or just have housekeeping change the channel back before the next guest arrives. I don't think most people would care one way or another.