ah well i see how this has developed -
for the record - if you rmanager is a twat who schedules you for a day you can't work, or profit by working, they will lose out in the end, because you won't turn up, or they'll leave (which is a cost to the company) which is why most retailrs ask for peoples availability at interview, and only employ those they have hours for. To cite people not being hired for not having weekend availability is a bit daft - if i had evening hours, i wouldn't employ someone who couldn't work evenings - if i had days tues-sat i'd employ someone for those hours - for some people sundays are vastly more convenient and when sunday hours are to be filled - it makes sense to employ someone who can do them! Its really no different to complaining about tueday opening on th grounds that a store wouldn't hire you cos you couldn't do tuesdays......
Out of 10 staff i had on sundays - only one working mum - two older ladies, one single man, 6 students. If we'd stayed open later we'd recruit more students to fill the space probably.
Also, opening hours are no limit to working hours - we had shelf filling crews in at 4pm on sundays and a night staff and management generally didn't leave until 6 ish - people still work when the customers aren't there!
People often complain they can't get convenient working hours - supermarkets that open 24-7 generally have hours on offer sooner or later to suit anyone if they wait for the right thing to come up. extending opening hours just opens that out to customer service staff.