i'd never try and do that for any prolonged stretch in the US. too many idiots, and most drivers/motorcyclist just don't get it.
having said that, I've drafted off of guys on scooters plenty of times here in the netherlands, but usually for short spells. they'll make it clear if they mind or not - they either go with it, or take off.
last year i was on a group ride on a super windy day. i got flicked and was trying to chase back, but decided there was no way, and no point because the ride was almost over. just as i did that a guy on a motor cycle pulls up and nods at me to get on his wheel. i tried to wave him off, but he wasn't having it.
he paced me back, at a steady pace around 40 kp/h to the group over 5-7 murderous minutes. by the time i caught them they were winding up for the final sprint