I can confirm I am a licensed dealer and I understand that ADI does not sell to end-users.
This statement is designed to make dealers think that ADI protects the channel more than it does.
After all, it doesn't say:
"All products must be installed by a licensed installer."
Therefore, all that it would take would be to have a "licensed installer" on staff to check the box.
Also, many states don't license LV work, so what then?
The second part of the statement is clearly a red herring, as why does a dealer need to check a box saying that they "understand ADI does not sell to end-users."?