I say this reluctantly, but there are many pilgrims who do not want to take their new friends home with them... reference the previous thread about 'ghosting."
Also, the EU data privacy and data protection laws would never allow this...a central registry of all persons who walked the Camino. In fact, the Pilgrim Office does not keep the names in a database. Once your Compostela is issued, your name is gone...
My professional half can make a rational reason for remaining better records. But my online self understands the great risk involved. I do not want my information in any more databases than necessary for law enforcement purposes. The likelihood of misuse and abuse is simply too great.
This said, I carry slips of paper with my e-mail and iPhone number for texting. I use a piece of paper set up like a "For Sale" poster with the individual contact tags pre-perforated or partially pre-cut. This allows me to easily tear one off. If I choose to give out this information, I do so.
Still and all, it does not prevent "ghosting." Plus, you should SEE my spam. Presently for every legitimate mail message I get, I receive three totally spam messages.
Fortunately, I use a VPN and have developed an ongoing, daily, program of screening spam at the gmail server. I set up rules to 'head it off at the pass.' it is very much a game of 'whack-a-mole.'
Hope this helps the dialog.