Yes. MAME files are handled very differently because we don't have any way of knowing what type of MAME rom set you have and moving/deleting files in merged/split sets can break things pretty badly. MAME is typically distributed in one of these versions: merged, split, non-merged. In the first two dependencies of a game are shoved in other files so that you only need each dependency once (saves a ton of space), because of this if we move/remove one of those files it breaks every game relying on it. A lot of the tools to do these operation on these games works differently (or not at all) so that users don't accidentally break their sets.