Sometimes, you can choose your customers. You make it clear who your target audience is and most people will clearly understand if they should self-select in, or pass on by.
Sometimes you cast the net pretty wide. You roll out the welcome mat and invite everyone in. Here's our experience, here's our price, take it or leave it.
That's not necessarily a bad thing.
But let's say you have a customer in good standing - they haven't purchased in awhile. But they've given you their email address and some other demographic information. They aren't causing problems for customer service, and as far as you know, they were satisfied with their last purchase. (You might even notice that they sent a complimentary Tweet about the experience.)
Why on earth would you do anything to make them think negatively about you and risk future business?
A few years ago for our anniversary, my wife and I stayed at a hotel we'd never stayed at before. It wasn't part of The Official Hotel Chain of the Lamb Family, but it was the right hotel at the right price in the right place for the events we had planned. At the front desk, they encouraged us to sign-up for their membership program and we said "Sure, why not?" We didn't know what our future plans were, but if you can earn points towards free stuff, we didn't see the harm. They also moved us 10 floors higher in the hotel and I tweeted out a thanks for that.
Fast-forward almost three years. We haven't had another stay in that hotel chain since. We just don't have opportunity to travel or stay in hotels much, it's mostly just the one time a year. So as we approach our anniversary, I start receiving emails from the hotel chain telling us that they're about to close our account and we'll lose all our points. (Oh, I can book a stay, buy points or get their credit card if I want to keep my points. And guess which two are links in th email.)
You're going to kick me out?
As near as I can tell, the cost to keep me on file is next to nothing. The cost to send emails every so often to keep their name top of mind and that's about it.
Instead, I'll probably receive more of these emails over the coming months, seeming more and more frantic and then one day, the points will be gone. And then the next time I go to book a hotel, I'll subconciously rule out the chain that kicked me out of the club.
Look at your business. Do you have any practices that are inadvertently designed to limit future business with fringe customers who aren't a cost burden now but could generate future profit? Are you doing anything that will cause bad word of mouth?
Exclusivity, scarcity and deadlines may be great tools to motivate that first sale but sometimes they make lousy retention practices.
You're going to kick me out? Fine. See if I care. I didn't want to be in your stupid club anyhow.