Coaches can coach from where ever they want - the sidelines, the press box, the school window, forklifts, trees and from the stands. If they are on the sideline, they have to stay in the coaches box, other that that there are no restrictions. Both teams do not have the same access to these locations. If the home team has a forklift, the visititors would have to bring their own.
The officials have no control (or interest in this). We worry about what's on the field.