As I'm working in graphical design market, I deal with those things on daily basis.
If I get my materials from my customer (photos, artworks, logos etc.), I require paper saying all materials he provided are legal to use by me in creating advertisement/large scale print etc.
If I'm creating advertisement from scrath and using photos from the web, I have to buy photos with proper license or make agreement with author of particular photo.
Even software I use at work have commercial license because I'm using it to make profit.
So in my opinion authors of particular add-ons should be asked for permission before relasing video on "monetized channel" unless license distributed with add-on say otherwise.
Probably majority of them will just shrug and say: "Sure. Free promotion - just give credit in video description or end credits", however I cannot speak for others.
Enjo said:
It is a moral problem:
- Orbiter gets more promotion this way
- People get paid for something they haven't done
- If the above is accepted then what do people who don't attach ads get from it?
Personal satisfaction? Feeling of fullfillment from fact that they've shared their knowledge? Ego boost from number of views/likes?
Motivations can be different for each single video maker.