I really didn't want to take part at this discussion as I already expressed my thoughts about all this debate about samples, licensing, unfa and Carl Irwin's videos, etc. in the unfa's rocketchat. It's an interesting topic, nonetheless, and it's important to grasp as much as we can.
For the moment I just want to point out a thing about incidental inclusion.
I'm not an English native speaker nor a UK citizen, however the word incidental seems connected to a random or casual event. I really doubt you can deliberately use something in your work and then say it was incidental.
The incidental inclusion of copyrighted work, despite not being 100% clear, has reached a more or less agreed meaning in the copyright realm.
For example, UK Channel 4's Producers Handbook has a little chapter dedicated to the incidental inclusion: https://www.channel4.com/producers-hand ... -inclusion
To cite the most relevant part:
Note: in the case of musical works specifically, if the work has been deliberately included, then the Act states that inclusion of the work should not be regarded as incidental.
Ref: https://www.legislation.gov.uk/ukpga/1988/48/section/31