Please, don't make him (and the latter) disappear after he is done.
The marshaller doesn't just disappear. It walks away and they it will disappear.
It looks too unrealistic! Also GSX vehicles collide with each other (they don't give way).
As explained so many times on the forum, GSX vehicles are not really aware of each other because, if they did as you are suggesting, a whole new class of problems might appear, like deadlocks on the limited space in a parking.
So, we try to prevent their conflict by acting in the startup times and their position. But it cannot work everywhere, because it depends by the scenery too. Which is why, you are being given the ability to customize their starting positions precisely, which usually can fix the few remaining cases of vehicles clashing into each other.