Demand Surrender, Demand Gift, Demand Tribute and possibly others do not work correctly: the recipient cannot accept those demands, both because the default message is a refusal, and because nothing accepts if you go ahead and accept. I think all other demands are not automatic, and those do not seem to be affected by the Demand problem. So yes, you can safely accept a Demand Surrender.
Oh, and Emergency Building lasts eleven turns, and not ten as advertised, if you do not turn it off yourself; I don't know if that would qualify as a bug though.