I do not agree to this part at all. If it's true, what GIC is for? GIC of 10K is for your living expense. Even if IO asks about how you will manage, or how much funds you are carrying, you can simply say just 1000 CAD cash rest I have my GIC and that should do.
Now about carrying cash, you can carry as much as you can (as long as it's legitimate). You need to declare any amount above 10K doesn't mean you can't bring. It just you need to declare it at POE. So once again, if you really don't need that much cash, you needn't worry about carrying so much of cash. Yes you can carry American Express Travelers cheque or any travelers cheque for that matter. GIC gets activated same day when you land, you need to visit a branch and you will ahve a chequing account, savings account and GIC + if you wish, you can get a visa with a limit of 500CAD.
Cheers!