[HereInTheHeartland]

“They never had a problem with charter buses before.”

That I don't know. I don't have the knowledge base to know what is or isn't needed.
I would think a bus going down an interstate would be a pretty soft target however.
I think the cost of Obama’s many vacations is an issue however overall. I don't have the numbers; but it seems he has spent much more than any other President.

[tobyhill]

He's not really even using the buses. He's flown in then takes the bus a couple blocks to the location.

It's more Obama stagecraft.