I think the 3 times before lockout is pretty well thought out. It leaves room for some mistakes but still makes one think bit ahead of time before queueing.

I never had actual problem or annoyances with DF system before the patch, but as I see many other has had issues with it so this lockout system is very welcome change.

And... even if you happen to fail the 3 times, it's only 30min ordinary penalty. I was prepared for something like instant ban until daily reset.