If I understand correctly that use case will only be practical with a dense web of trust, but that's not what they are going to focus on to start with. So that's why I'm confused, since they aren't going to start out with the most interesting feature.
A dense web of trust is only needed for credit. Otherwise, there just has to be at least one path with enough liquidity for any given transaction.
If you want to setup a local gateway to help your friends get cash into and out of the system, you can. Here's what you can do:
1) You set up your account to trust at least one gateway. Your friends pay you IOUs from any gateway you accept. You hand them cash.
2) Your friends set up their accounts to trust at least one gateway that you do business with. You pay your friends IOUs from any gateway they accept that you support.
The downside of this setup is that it doesn't allow you to grow into more of your own gateway, but it also doesn't require anyone to trust you. If you want more of a growth potential and think people would be willing to trust you, you can do this:
1) You set up your account to trust at least one gateway. You setup 1-to-1 offers between your own IOUs and IOUs at at least one gateway.
2) Your friends give you cash, you pay them with your own IOUs. You require them to trust either you or at least one gateway you support.
3) Your friends can pay you with either your own IOUs or IOUs from any gateway you support.
4) You try to encourage your friends to hold your IOUs rather than the IOUs of an other gateway. You can do this by keeping your transfer fees lower than that of other gateways. You can do this by convincing them that the risk that you, someone they know, will default is low. With your IOUs, they can costlessly switch to the IOUs of any gateway you support (so long as you aren't "out of stock").
You don't need a dense web of trust. All you need is every account to trust at least one major gateway and healthy paths between any two major gateways. And even if you don't have that, unless an account is an island, you'll almost always still be able to find a usable path.