On 2007-11-05 13:36:41 +0000, "
said:

I know it might result in stains, but are there any other dangers?
These tiles have been on the walls unsealed for a few years now (I
didn't fit the original bathroom, I'm just picking up the pieces) and
I'm tempted to leave them as they are. I can cope with the risk of
stains, but I might be a bit more nervous if they're going to jump off
the wall or anything.

Peter

They won't jump off the wall. However, if there is any staining or
splashing from cleaning products etc. you are basically screwed with
unsealed travertine.