How old is your bike?

I've had issues with poor clamps allowing the cage to slip. I'd imagine you'd have the same issue with the zip ties, and rapidly find them to be annoying to use.

Anyway, if your bike has standard tubing sizes from the 1960's to 1980's, then I'd encourage you to track down some vintage cage clamps. They won't hardly be any more expensive than the hose clamps, and will be more secure and look better. Be careful of some of the cheap repro imports.