So, I could insure a $20,000 car with a $20,000 deductible and the lender wouldn't have a problem with it?
If you're that stupid and the insurance company says OK, then I don't see why not.
The whole point of requiring comp and collision on a vehicle securing a lease or loan is so that when you total the vehicle (or it gets stolen), the bank isn't left holding the bag. Having a high deductible defeats this purpose -- and the extreme example posited above is entirely equivalent to not having comp/collision coverage at all.
You didn't ask if a BANK would allow it - in fact, you didn't mention it was a financed car at all. I stick with my comment
I have full coverage on a car that's paid off and I have a relatively high deductible ($1K which I have on both my cars - including the lease) on it. Yeah, I could cancel collision, but why? When the car's worth less than what I'm paying annually to cover it, then I'll think about dropping collision. I could cover the cost of replacing it if it was totaled now, but again - why when I can insure it?
Again, I've never personally seen a bank tell you what deductible to get and I've financed a lot of cars through a lot of different banks and credit unions. I was just commenting on my experience