The gateway gets the whole request

[martinthomson]

This means that the client really needs to trust that the gateway doesn't muck with it. As a practical matter, this incentivizes clients to choose a gateway that is effectively the same entity as the target. They don't have to, but the amount of trust required of the gateway is higher if gateway and target aren't operated by the same entity.

We touch on this, but we could be clearer about it.