The thing about using a vehicle in front of you to act as a blocker, is that your field of vision ahead will be reduced, especially if you ride to the left of the lane to create a space cushion. And if the vehicle ahead of you does crash into a lane changer, you will likely have no escape path. AND, that 4 wheel vehicle can probably brake in less distance than you. Maybe if the vehicle was a reasonable distance in front of you this could work, but not if you are tailgating it.
If you are going to up your delta, and therefore your level of risk, at least up your level of defensiveness. Cover your front brake, ride to the left and have at least one eye on every wheel of every vehicle you pass, looking to see any side motion whatsoever of a turning wheel (wheels are quicker to spot first than a moving vehicle).
The biggest risk of speed is the faster you go, the more severity of injury if you crash. Don't do anything on the bike that won't allow for an escape path. If you don't have an escape path (braking, swerving or accelerating) than you probably shouldn't do it.