3. General legal considerations - I am by no means an expert on this - but this is a relevant discussion - when are you (illegally) eavesdropping by participating in a p2p network ? What are you allowed to do with the data/metadata (e.g. INVs and TXs) you receive ? What can you as a p2p user (legally) expect them to be used for ? Do we actually expect any regulation to cover here at all ?
For a Swiss company, this law here is relevant:
http://www.admin.ch/opc/de/classified-compilation/19920153/201401010000/235.1.pdfAs for the question if collecting an IP in connection with other data is covered by this law, you can consult several legal documents from Data Protection Agencies in Switzerland and in Europe.