How do I send mass friend invites without raising red-flags?

I have a list of over 2000 people I'd like to friend request on facebook. they are targeted users. I sent out about 20, before getting a facebook message telling me to chill out. So, I spaced it out and got about 100 invites out last night. Today I got on, and 62 people accepted my friend request. Prty good, considering I sent out about 100. So I tried to send some more invites out, and Facebook put a 2 day hold on invites. WTF? I could understand if pple were denying my friend requests, but mostly ever1 was accepting them, so why would that raise red flags?

And more importantly, how can I send friend invites without raising red flags?