When it comes to financial responsibility laws for vehicle liability, my current understanding is that the state where the vehicle is registered in is the deciding factor for legal compliance with other states being driven through due to some sort of reciprocity or the insurer having agreements with networks of underwriters where coverage limits expand as needed to at least the required minimums.
However, there are alternatives to conventional insurance that I am very interested in, such as surety bonds, security deposits held by the state, or even self-funded insurance as a small business fleet. Surety bonds require a third-party which I would assume acts like a traditional insurance policy insurer to have elastic compliance on an interstate level.
But what about the security deposits at the state where the vehicle is registered? Is a receipt / certificate of satisfactorily meeting financial responsibility in the home state sufficient for interstate travel?