i have a couple of older gibsons with lacquer cracks. mostly on the body, but one also has them on the neck. if i remember rightly they're caused by quick changes of temperature, where the wood expands and contracts quicker than the finish.
anyway, they've never caused me any problems and i'm happy enough with their appearance, but i'm not sure i'd be too happy to see them on a brand new guitar, if these cracks are the lines they're talking about.
as others have said, have a good look and think before you buy, and it might be worth it to look extra unsure and see if they'll knock more off the price!
good luck with it anyway, you never know, it might be the best guitar you ever play and a friend for life!