If I am paying for those routes then I have a contractual right. If you don't want my redundant feed, and the route advertisements that go with it, then don't take my money.
Please detail the exact costs of a, BGP inserted, routing table entry. Is it, maybe, 50 cents? Now, how much are you getting for a DS1 link? What does that cost, exactly, considering that an outfit capable of setting up multi-homing are probably the folks that your techs never hear from, but once a year? That appears to be a margin that is far above keystone. How greedy do you want to be?
The point you're missing is that the important issue is not whether or not your ISP will carry and advertise your routes, since you are paying them to. The important point is whether or not anyone else will carry your route. There's no reason for a RIR to make a microallocation just so you can advertise it to your ISP. If the advertisement was purely between contracually bound parties, the block could be part of a provider's larger block and there would be no difference. The only reason for a microallocation is to get a party with whom you do not have a contract to accept a route that they would not otherwise accept. Why else would a multihomer want a microallocation? Why not just use a chunk of a provider's IP space? The only answers are: 1) We don't want to be held hostage by a provider. (No good, not a technical justification.) 2) We want others to accept our smaller routes. (Why not do it by contract?) DS