I try not to rant here, but the message is both simple and important: make it easy for your clients to do what you want.
Example: I make a hotel reservation with a chain I’ve never stayed with before (because it’s at the venue where I’m speaking.) The chain wants me to sign up for its frequent sleeper program. Fine. I enter all the info for my reservation, then I get to enter it again for the frequent sleeper program. Why not, after the reservation information is complete, say, "Hey Bill, we’ve got all the info we need to add you to our program. We’ll start with 1000 points. Just say yes, and be ready to give us a password.