In cities such as San Francisco and DC, and here in New York, condoms have been used as evidence against alleged prostitutes. (In DC, police have been accused of claiming that suspects carrying three or more condoms have an intent to sell sex in "Prostitution Free Zones.") Change.org asserts that the practice has had a chilling effect on safe-sex in the sex industry, with some undergound brothels refusing to keep condoms on premises. And the website also cites anecdotal reports that regular businesses have been reluctant to distribute NYC's free condoms because they can also be used as evidence of "maintaining a premises for prostitution."
The use of condoms as evidence is not specified under law as either acceptable or unacceptable, but a bill that has been languishing in the State Assembly would change that. If passed, the possession of contraceptive devices would not be permitted in specified criminal or civil proceedings as evidence of prostitution. The Sex Workers Project has a petition going to support the bill, so that one day people won't have to choose between jail and STDs. (In San Francisco, a study found that only half of sex workers use condoms with first-time clients, and fewer with repeat customers!)