If I remember from previous research on the topic the days you're referring to seemed to be celebrated in succession, so unless they were each born one day apart it wouldn't make sense. Additionally, if memory serves it was during one of those times where the kids were all killed by a tornado, again even if they were birthdays not a ringing endorsement.
With that said, my wife and I kind of celebrated ours for the first time last year, and nothing happened. We did disassociate a couple weeks following my birthday though. Best gift ever.