The FAA people in charge of issuing launch licenses worry about this kind of thing -- and commented a while ago that they'd lean heavily on the NASA Planetary Protection Officer for cases like this.

http://www.thespacereview.com/article/3260/1

> “We don’t have the expertise in-house when it comes to planetary protection,” said Kelvin Coleman, acting deputy associate administrator for commercial space transportation at the FAA. His office licenses commercial launches, a process that includes a payload review that would, potentially, include a planetary protection review. He said the FAA would “be leaning on” NASA to provide planetary protection expertise.