thank you both for your replies.

I assume crinkles - if they're severe enough - can cause a premature failure of the liner. Is that correct?

Can the crinkles - if they're "minor", affect the structural integrity of the wall itself? I definitely don't want the wall to collapse...if that's even possible.

Is there a visual test to determine if crinkling is severe enough to warrant a replacement wall? I could take some photos and post them tomorrow.