By Dan Levine SAN FRANCISCO (Reuters) - Airbnb promoted a series of policy proposals on Wednesday that the home rental company said would address concerns raised by officials in New York and San Francisco over how the company operates. Lawmakers in both cities have accused Airbnb of exacerbating an affordable housing crisis by encouraging property owners to remove long-term rentals from the market. San Francisco passed an ordinance earlier this year that would fine Airbnb and similar services $1,000 each time they process a booking from an unregistered host.