I would assume agents would be able to let players know about the legitimacy of this. None of it happens in a vacuum, after all.
If Broussard is making this up he'll probably have to issue a retraction but it's unclear as to what sort of 'proof' would validate it one way or another.
I guess there are a few things that could happen.
1) Jordan could come out and say look this has been a long difficult decision and i respect the mavs and all they did throughout their process. I also want to clarify that Marc Cuban did not contact/harass me or my family members and carried himself with class and dignity throughout this ordeal. Ultimately LA is where my heart is and we will move forward from here. I wish everyone involved can move forward from here (this is not likely obviously, but is possible as a means of a damage control for Jordan).
2) Cuban could sue Broussard and his cell phone records could be subpoenaed as part of the case where they would show he has at no time texted anyone in his family. They also could show evidence that Cuban clearly knew where his house was prior to the date. (obviously this is the least likely)
3) Some mystery family members come forward and says "it was me! i told broussard that, that cuban was harassing all of us asking where dj lives all day"
Obviously this is all much less entertaining than what will really happen which is most likely, nothing. However, the fact there is a 100k challenge and twitter exchanges is more than I had hoped for TBH.
