Say I have two video tracks in a Vegas Project - Track 1 and Track 2.
Now lets say I place video EVENT A on track 1 and then place a different video event - EVENT B which is exactly the same duration as EVEN A - on track 2 and I place EVENT B so that it is situated directly beneath EVENT A.
All levels are set to 100% so basically EVENT A completely over-shadows EVENT B.

In the situation described above - does Vegas process EVENT B during playback or rendering? or does Vegas recognize that EVENT B is basically obsolete and ignore it?
Or let me put it another way - does it make a difference (as far as playback and/or rendering) if EVENT B is left as an active event / or if set to mute / or alternatively removed from the timeline altogether?

Thanks.

There's no need to mute the lower one. It will be ignored. You could do a bunch of them as a test and see if there's any render speed difference but I think you'll see that it's totally ignored.

Ok. Thanks!

The only time I can see it might make a difference, is if the media properties do indicate some alpha information, even if there is no actual transparent pieces.

Another transparency issue that can happen accidently is if while mousing around on the timeline the opacity of an event gets dragged down to something imperceptible, like 96%.
Unless you are zoomed in enough you might not notice the opacity envelope so close to the top edge of the event. You also probably won't see the effect of this mistake visually in the preview, but it would certainly affect the render time no matter what is below it or whether the events below are muted.