Thanks for all the replies.  Gosh I'm glad I'm not a seller. 

It's one thing to chose how long to send an item, and though Aust Post hasn't lost anything of mine lately, the time they take to deliver is sometimes really weird.

I'm glad I've left 'late' deliveries blank. It hadn't occurred to me to lie, but I'll keep it in mind. LOL

I prefer to allow weeks (or for overseas purchases a month or so) before I worry about a missing item...and even then I contact the seller first, not eBay or PayPal.

I've learnt a lot from asking ajust  simple question.  Thanks.