Giving non-profits a bad name

TiE in the Valley runs a good annual conference - and very reasonably priced. I did go couple of years ago, and they send me annual invites. But this year they hounded me with phone calls. At least 5 times. With caller ids which showed just 3 characters. If they did that to many others, I think they could be in violation of their non-profit telemarketing status.  They have a loyal following - not sure why they have to be so aggressive.