But use it is not the same as give it to somebody else.
GPL as example requires to deliver a copyright and warranty disclaimer, the licence text and source code (on medium, as written offer or as link).
So if you convey Ubuntu MATE, you have to provide source code, too.? Where can I find the right sources of the raspberry image?
And a disclaimer where to find all the copyrigths and the licence text?
But is this enough? Or are there non-free parts in Ubuntu MATE or parts under other licences?