I think it would be fine as long as the beardie can come out and play for a while during the day....but the tub is a great idea as well.
Personally I dont even leave my beardie alone for an overnight trip. I have a sitter come in and take care of her and the other lizards.I want no part in the beardie guiltizm when I come home...lol.
beardie guiltizm - when a bearded dragon is mad or trying to give you the guilt trip because...
A. - lights didnt come on or off at the right time
B. - not the right veggies...or no veggies/crickets
C. - did not get enough time out
D. - didnt get tucked in properly for bed/ missing favorite blankey
E. - just wants to lay the guilt trip because....it can...