We may not. However, without ULA, I question whether people will bother adopting IPv6 at all. If that's what the community desires, then so be it. However, I expect market forces will drive the requirement for ULA. If it's missing, I expect a repeat of another happening with IPv4, that being people picking random address blocks to use.
Market forces aren't driving a desire for ULA. They are driving a desire for cost effective globally unique addresses. A good part of the market does not care about routability or not of those addresses. A meaningful part of the market does. ULA will meet the needs of the former, but, not the latter. Globally unique address assignments to end users with a rational policy (the v6 equivalent of 2002-3 at say the /48 or /56 level) would meet the needs being addressed by ULA and needs not being met by the ULA proposal.
As for the ingress filtering issue, education and contract terms are two good answers. I'd like to see network operators considering ingress as part of their aggregation router buying decisions, of course.
Contract terms are a negotiation. As soon as dollars are available for the sake of abandoning an entirely artificial limitation on the use of addresses, guess which way that negotiation will go. We'd all love to see that, but, regardless of the capabilities of the router, the reality is that when a customer dangles enough dollars in front of an ISP for advertising their non-routable space that will do no harm by being advertised to the rest of the internet, they're going to do the following: 1. Warn the customer this may not work out so well for them. 2. Do everything they can to get the route accepted. (If you think this will actually be hard, think again) 3. Take the money. As to why 2 won't be hard: Think of it this way... Each provider is going to be faced with such customers fairly quickly. They're not going to come to the techies and ask why not and go gently into that good night. The sales people are going to see $$ for doing this at each and every ISP and they're going to drive negotiations between management at the providers to trade these "harmless" routes. This decision will not be made by the operational community, but, inflicted on it by management seeing $$ for doing so. Owen -- If it wasn't crypto-signed, it probably didn't come from me.