Oh yeah, you GOTTA crumple the numbers. That's a given.
The officials will complain about it, so you have to smooth them back out before pinning it on.
Just so you rookies understand WHY you crumple it and then smooth it out: the stiff Tyvek flaps in the wind and makes a horrible sound that everyone hates. Plus, when you're attacking from behind, everyone will hear you coming.
You smooth it out to make it readable by the photo-finish cameras.
Cool stuff.
And I've seen people use that sticky spray stuff instead of pins, but the heat/sweat/etc doesn't serve it well.
Amazing how much