I can understand the impulse, but think it was handled poorly—to just mention it on Twitter the day before an expected jailbreak, and with no mention of new features, etc. I actually switched to Lockinfo back on iOS 5 so won't really be affected anyway, but I feel for users who were excited to update tomorrow.
I will say this: I've only paid more than $5 for three apps in my life—ISX, BiteSMS, and Lockinfo. So far, only ISX—the most expensive and most recent purchase—has charged for an update. Both the others have undergone major revisions over several versions of iOS without charging existing customers.
(Edit: On the other hand, ISX does come with Messages+ integration, making it sort of like Bite and Lockinfo in one...)