If you can sustain that pattern indefinitely, perhaps not.
If you're getting a quick boost at the expense of your long-term reputation, for example because customers signed up for your service and then you left them high and dry, then I think you should.
Case in point: Around 2-3 years ago, certain recurring billing services made rather sudden changes to their pricing, which very publicly upset a lot of their users. I bookmarked those stories at the time, knowing that sooner or later I would be looking for payment services to use with my own companies.
Recently, that day arrived, and we immediately ruled out anyone who appeared to have acted in a way that screwed over their existing customers. I have a list of names of some of the key founders who were identified at the time, and no company of mine will ever buy any service from any company of theirs. Given that they have demonstrated that they are likely to be incompetent, unreliable, or both, there is simply nothing they could ever say or do that would make us trust them with any important part of our operations now.
It depends if you're "getting rid" of existing customers by forcing them into the new pricing. I don't think that's ever a good idea - they signed up at a specific price and shouldn't be forced to change if they don't want to. That's how Server Density have implemented this change - it's for new signups only. Existing customers can move if they wish but they'll never be forced to.
The idiots being scared away doesn't necessarily imply that everybody who is scared away is an idiot :-)
Yes - you will cut out some very nice people who would make lovely customers by segmenting like this. However if this ends up:
* getting more money using the new pricing model
* removing a large chunk of support costs by getting rid of the high-cost, low-value customers
.... as a business should I care?