Yeah I get something similar (from time to time) in Asda; they ask me for my postcode. To be honest I give them one from 3-4 streets away (like half a mile away,) as I don't want to give my actual address.
When I was in New Look 3 months ago (buying a top,) the girl said 'do you want your receipt sent via email?' I said 'umm ok...' And I gave her my email address. I have not bought anything from there since, and yet since that day (in early March,) I have received approximately 80 spam promotional emails from them.
I do get receipts sent via email when I buy something from Argos, (and have done for a couple of years,) but I only get about 2 or 3 'promotional' emails a month from them. So because of this, I thought it would be OK to give New Look my email address. Obvs not! 
I don't like store cards either, as I'm a bit sniffy about every last thing I buy being stored on some database. They have a record of what sells, and how much it sells, so why do they need a rundown of each individual customer's items that they bought in their food shopping? What's more, I had a store card for Tesco (up to about 3 years ago,) and kept getting vouchers for money off, and also 'buy-one-get-one-free' vouchers, for items I never ever bought! 
But yeah, like the OP, I am not keen on telling strangers my address. I even get a bit sniffy about the pharmacist calling out my name and address when I'm picking up a prescription. 'Mrs Jen? 55 High Street?' Great. Now a dozen strangers in the pharmacy know where I live! 