I'm quite surprised to see this answer go, especially with a "spam or rude/abusive" epitaph on its grave. From what I can see, the last revision of the answer had 24 upvotes, 2 downvotes and looked like this:
It can be done, with a few precautions.
Don't put them in the same bed with, especially when the batteries are charged.
Don't put them in the upper bed, especially if the bed isn't sturdy.
Don't heat them up when you sleep with them.
Be careful about leaky or old batteries. Acid spill can be bad.
I would also recommend against sleeping with them when they are being charged with or discharged at high current levels.
It is generally safer to store them away from your bed, preferably in a acid resistive isothermal chamber.
Regardless of the usefulness of the answer, I believe that having a history of content deleted as abusive is a pretty strong black mark against the account (involving rate limits for questions, answers and comments and more CAPCHA) which the user doesn't seem to deserve.
Or did I miss something that happened behind the scenes?