I'd wondered who paid if you got quarantined...

In Hong Kong at least, the government offers to pay for your hotel room, feeds you, and sends you a box of chocolate in thanks.

From http://news.bbc.co.uk/1/hi/world/asia-pacific/8032753.stm:

Travellers in a Hong Kong hotel have been speaking of their frustration and boredom as they endure a week-long quarantine imposed as a precaution against swine flu.

Officials cordoned off the hotel on Friday after it was discovered that a Mexican who had been staying there had tested positive for swine flu.

[G]uests who had been taken to hospital for tests following the discovery of the Mexican man's case had all tested negative.

Authorities are offering to cover the cost of rooms and expenses while Hong Kong's health secretary sent a box of chocolates to each of the guests to thank them for their patience, reports said.

Guests also noted that the staff and officials had been trying their best to keep guests happy.