@Lucy_R SF host here, and the situation is a little different than Air not wanting to pay taxes.
SF passed a law in 2014 that hosts have to go through a permit process to host legally and Air BNB will pay the TOT(transient occupancy tax) on our behalf to the city. TOT is a part of any SF reservation you book. SF got mad because barely any hosts registered for the permits, bc the original process was laborious and had not been completely ‘approved’ by a general vote…fast forward to Nov 2015 when another law was passed upholding the 2014 permitting law, and telling hosts if you don’t register you are subject to a $500/day penalty, and we the city of SF are now enforcing the penalty. Fast fast forward to June 2016 when still 75% of host in SF are unregistered, and the city just passed a law that would fine Air/ Homeaway/etc $1000/day per unpermitted unit for listing unregistered units. Air has started this lawsuit because they do not think people listing unpermitted units is within their control, and they should not be held liable, etc.
Air isn’t trying to skip out on taxes, as regardless of permit status Air is still collecting TOT. They are trying to not be fined for letting unpermitted hosts be on their platform. Not saying that is any better, but that’s the long and short of the drama.
PS- The permit registration is beyond EASY, the city of SF revamped it to take about .5- 1 hour as a walk in appointment, $50, and you get your permit in 7 days. There is really no reason to not get registered, unless you do not meet the permit criteria, which includes multiple entire apartments/homes in SF(basically prop mgrs) or you are a renter and do not have landlord approval.