No worries. Put the Kindle in a ziploc bag. There have been reports of people scrambling for them at the bottom of a hot tub for a couple minutes in a ziploc, and the Kindle came out fine!
I don't really take baths (unless I shower first - I'm weird like that) but occasionally I think it would be nice to do so and read my Kindle. The next thought is it in the bottom of the tub, drowned. That is just too scary of a thought. I mean, I know I can get another one and that everything is backed up on the Cloud, but no I just can't ... I have too many books on there that I put on myself (r2rs and such) and notes and all that. Plus, I don't want to see it die. That's just ... sad.
I have sometimes brought my iPhone in there, but never my Kindle. Now I won't risk that at all. Only regular books. Fortunately the book was second hand and I hadn't gotten too far into it to get invested.
That's alright.; I've done it myself when reading in the tub and have no one to blame but myself. I'd rather dunk my Kindle than my physical books actually. I can always replace an e-reader or use another device and all my ebooks are backed up so no physical loss.
The last time I left a tub with water in it there was a SPLASH and a very annoyed cat that had to be wrapped in a blanket and told how silly he was. Heh.