Yes, if she sees you, she may stop laying, and become eggbound, leave her alone till you are sure shes done.
And sometimes they will eat but still need to keep laying, other times they wont, it just depends on the female.
yes female chams can sometime abandon their hole digger for laying eggs if you disturb them. best is to leave them alone and check on them the next day. let her rest and when she makes her way up on her vines then start feeding her with calcium for every feeding also water frequently also check out jannb's blog about egg laying. it is very informative.