Yikes, that's exactly why I clamp mine too.

Plastic cuts into wire insulation over time, especially on anything that vibrates. Velcro is reusable and won't nick a jacket. But zip ties hold tighter and don't come loose in a high heat cabinet. The old guy probably had a point about service loops though.

Spraying oil on frozen fries just adds a layer that traps steam underneath unless you spread them out in a single layer with room to breathe. Cranking the temp higher does the same job without extra steps, and it works on any brand right out of the bag. Save the oil spray for fresh cut potatoes where it actually does something.