Absolutely - But a company can decide if they want to give their users the option to do so (if possible) or if they dont want to.
Like back in the days when cd´s suddenly came with the copy protection.
I´m not saying that I dont want this and I´m not saying that I don´t like the idea - I´m just saying that I´d rather update through wifi, than risking someone copying my music because I´m playing on his Prime unit at a gig.
OK but it’s your choice to put the USB stick in there, and it’s your choice to walk off and leave it unattended. In the same scenario, I wouldn’t do that. The stick is in while I’m there, but if I’m not, then it comes with me.
One possible solution is to simply not allow copying while a track is playing. If it’s in use at a gig, it’s highly unlikely that the other DJ will stop the music to copy your tracks.
May be something soon to happen is known to denon dj but that must not have usb drive to drive copy’s. Like tidal record off line. Tidal might be happys with tidal files stored in prime drives but NOT if he drive to drive copy features are inside machine too.
If Tidal do allow offline storage at some point, then the files will undoubtedly be copy protected, locked to the hardware or user account etc.
You are from tidal ?!
You are from tidal?
No, but I have common sense. They will protect their assets to the best of their abilities.
O you were the guessing
No I wasn’t “the guessing”. Tidal are not going to allow you to download unprotected files.
It’s safe if the drive he can’t copy to or to from
That’s probably why denon haven’t put the function for copying files in and out of the primes - piracy! 
yes yes, for sure. 
I’m guessing you probably have your rig sitting on your moms coffee table with wires strewn around the whole room.
I can’t believe that a copy paste function does not exist because of pirate reasons or for someone may stole music from a usb stick. We are in 2020. Maybe there are software or hardware limitations regarding active sources at the same time, this it’s ok if it happens. But anyway to move, rename or delete songs direct from prime 4 and between sources it could be perfect.
Off course Chris. Some of us have noticed for some time that unfortunately in this forum there are user profiles managed directly by Denon, none of us are stupid, and as you have correctly written, there are some explanations that have no rational sense, in in this case it is clear that the software has obvious limits.
Hello, yes maybe it is related to the OS structure how is built (crates, Playlist, prepare, file folders) it is 1 structure all these and each source has all of them assigned so to have 2 sources active at the same time it could not be possible as you should have 2 structures active.