Hmm, very risky, depends on your bathtub really.
I wouldn't risk it just for the safety reasons and really, on your place I wouldn't rely on forums for answer with such a risky question
I remember ages ago on a different forum I asked if a standard glass splashback can be used for a kitchen worktop, and how heavy it will be and if two people can carry it, and everyone was like "yes yes, you'll be fine".
Needles to say, week after that I had 4 people carry the worktop. Some questions just can't be answered on forums