This is a case like the old philosophical question of "does a tree falling in a forest make a noise if no one is there to hear it?"
Does an event fire even though the app has no event code to handle it?
The answer to the "app" question is yes, with the proviso that the event will limited to the place that WOULD have fielded it. So if you do something to the subform then events on the subform will fire appropriately but the main form will do nothing unless the subform's event code "reaches out and touches" the main form. Technically, it is the Access event that triggers the app's event code. Where you work is where the events occur.
The answer to the "tree" question depends on whether you ask the question using "sound" vs. "noise" since they have different connotations.
Ever since my liver went wonky on me, I'll have to demur on that wine. Enjoy my share, take a sip for me.