I don't know exactly how to find it, I am pretty sure I've heard that on TV some time ago.

However in Italy, for instance, the Legge 352/1993[1] says explicitly to use proper "containers" in order to favour the spores' spreading.

That's a generic normative then local authorities could rule other details on harvesting and selling them.

- [1] http://www.salute.gov.it/imgs/C_17_normativa_1787_allegato.p...