Without it there are oddities in the TMA airspace data. For example the little triangular fillet of Paris TMA between DPE and VEULE is actually the filler between M605, L612 and R50. In fact, all the airspace in the area is class E with base FL65, and the triangular area is the only bit not within 5 nm of an airway c/l.

I think the main thing is to document the convention you're using in some way that the user can be aware that there may be class E that is not shown.