Which stores allow you to use a competitor coupon?

[momto5kids]

For example would London Drugs allow you to use Target store coupons? Or Walmart allow you to use the $25 dollar Superstore coupon you cut out from their flyer? Also does Canadian tire PM?

[lizzie bargain]

I know my Co-op in Calgary will accept competitor coupons-for eg I have used a 50% off Tide coupon from Safeway there before. I did ask at my Walmart today if they accepted Target coupons and the clerk I asked said No.

[monkeycocoa]

Bed Bath and Beyond accepts Home Outfitters 25% off coupons. (not the print out one, must be the original coupon)