Could you explain these 'stub' files a little more (maybe share one): When I add a 1 sec silent mp3 file to my library it shows up as a standard track (not greyed out and with a time of 0:01).
This is correct. It is just a standard mp3 file. You are missing a couple of steps though.
First:
Add a custom tag - edit>>preferences>>tags(1)
[Display name: TimeStub] or whatever. [Save to music file as tag: Stub].
In the tags of the music file edit this field with the time you want to display [3:45] or whatever.
Second:
Add a virtual tag - edit>>preferences>>tags(1)>>define new tags
[Label: TimeS] $IsNull(<TimeStub>,<Time>,<TimeStub>)
Note: this displays a fake time. If you want it blank, like in my screenshot, change to: $IsNull(<TimeStub>,<Time>,>
Edit column display to show <TimeS> in place of <Time>.
Now if the Stub tag in the file has something in it, this will be displayed instead of the usual time.
For the grey effect edit highlight rules - edit>>preferences>>tags(1)>>highlighting: define rules.
name: Stub File >> rule: Time < 0:05 >> gray color >> + text?: check
And to be clear, 'banned' tracks should still be added to the Now Playing list but with a '-' symbol added to identify that they will be skipped.
Ok... that was not clear. I was basing my observation on the way the thumbnail browser was adding files as I expected and assumed they would behave the same. Perhaps I should look closer at the documentation. In my humble opinion, if they are not going to be played, they probably should not be added to the now playing list at all...
Edit -
After some reading I am undecided on my original post. According to another thread this should work as I intend as I am using an auto-playlist <https://getmusicbee.com/forum/index.php?topic=5412.0>
Bans also work for autoplaylists and AutoDJ, but in this event they are not added to the list at all (as opposed to added and skipped, as above).