The advent of the Internet has made it easy to for pretty much anyone to offer short-term vacation rentals—and over 200 of these operators in Marin, many of whom are renting their homes, are either unaware of, or are ignoring, a county tax. Over the last year, the finance department has searched for providers not collecting the Transient Occupancy Tax from customers, and an amnesty program approved by supervisors on Tuesday gives operators until the…