Had an interesting discussion at work with one of the engineers (he's signing up for the trial too) and we came to the conclusion that if left up to the end user they'll only use 1 subnet.
I tend to agree so long as you say AVERAGE user. Most do not even have a router so the number of subnets is not an issue for them (they use the supplied IPv4/32 single address as is). Those who do have a router will not have enough devices to need a second subnet. I have seen people with both Wired and Wireless LANs who separate the two into different subnetworks for control purposes. As I said, the ISP giving out /56s (in lieu of a /48) will allow them to get 4096 times the number of prefixes to assign to their customers while still allowing the customer to have the same number of subnetworks that the current IPv4/32 + Class-C LAN NATing provides.
Given the size of the block the ISP is being given, this 4096 fold increase in prefixes should be a large enough supply of prefixes.
