Re: They say not structural
Caveat - I can't see a picutre.
Hairline cracks in pools are generally just an eyesore and not a problem. Typically not until you can stick a toothpick in the crack is it concern for a leak. Even then most don't lose water.
How old is the pool?
Where is the crack?
Re: They say not structural
@wishIcould: you can post pictures using Flickr, Webshots, Picasa, Google Docs, Dropbox, etc. Just find the link for your picture, and post between two IMG tags -- clicking the little picture symbol on the edit tool bar will enter those tags for you.