This hasn't happened with any of my previous registrations, but I do wonder about how they found out about this new registration. Should I blame my registrar and think about switching, or are there other ways people find out about recent registrations?
I'll drop my registrar a line letting them know that it happened, but if there are ways people can monitor for new registrations, I'll just assume that my registrar is following their posted privacy policy. I do get astonishingly little spam (as in none) at the e-mail addresses they know about, so they must be doing something right.
For private use I probably would have refrained from registering my numbers, however in the business world it is nearly impossible to survive in a vacuum and profit.