Discover 5% back online shopping question

[Juss11]

I see discover has 5% cash back this Quater for online purchuses. Im going to buy a home security system at costco which will cost arond $1200. If you shop online you can pay by Discover,visa,etc. So would this be considered onine shopping? I could go to my local store, but then you would not get the 5%, plus I think its cheaper online.

[ObieGrad]

It should count.  The only case I could see it not working is if the security system is not directly sold by Costco.com and instead Costco is sending your information to a third party provider of security systems.