I was actually about to post a suggestion for the springs too (because I was about 3 minutes away from losing my streak last night), so I think I'll hop in and pad on to this one.
While a CS token would be nice, to me that seems like just yet another cash grab. I think it might be more reasonable that every day you miss you either drop 1 tier or X visits (10? 15? I dunno, numbers would have to be sorted out).
So to explain better, option 1 that I suggested: you're on tier 3, you miss a day, rather than drop to 0 you drop to the bottom of tier 2.
Option 2 that I suggested: You're at a 150 streak, you miss a day, you drop to a 140 or 135 or whatever streak.
Whichever it is, the punishment of dropping to 0 when you've been consistent for AGES is just far too harsh a punishment for something that, as you said, could be completely out of someone's control.