yes, unless you are an operator registered with nsm (or rowe or touchtunes for that fact) you cannot operate the jukebox and they will remotely shut the machine down and lock it out from being used.
"Oh" you say, "I'll just not connect it online and that will work."
Not exactly. Most internet jukeboxes will disable themselves if they are unable to "call home" within a certain amount of time of their last contact with the server.
With these internet connected units, about the only thing you can do is what ed has mentioned... dump new software on it. most of these units use standard touchscreen controllers and the software for them is available on maker's website (3M/general touch/ELO etc.)
the only issue you may run into is if they've used a custom DSP (Digital signal processor) for the audio output. then you might as well use your own motherboard and go from there.