Apologies, missed this one.

The position seems to be:

1. The Governor has decreed the tax should be paid.
2. The legislature has not passed any law requiring the tax to be paid or any penalty for not paying it.
3. The fact that 60% of tourists, (as widely reported in the local press), are not paying it, suggests that 1 and 2 above are true.
4. The threat that tourists will not be allowed to enter on a future occasion seems an empty threat as the Indonesian government controls immigration, not the State of Bali, (this is my personal opinion based on my understanding of Indonesian immigration law).
5. If properly legislated the sensible approach, (as in Malaysia), would be for the location where you are sleeping to collect the tax to do so, however, the hoteliers are declining to do so.

All the above said, personally I pay it it to avoid all the distractions of getting into some long conversation with an official demanding payment, possibly requiring me to move to another location to further discuss the matter, (whether they have such legal authority to do so or not), but there are those I know who simply refuse to pay it on the basis that it is a legally unenforceable scam.

Of course, a law could be passed today making it mandatory with a criminal sanction.