I think you're right. And I don't know that, if this is a negotiating tactic, that it has even a remote chance of being successful.
This is how I see it:
The deal Bubba signs is being negotiated right now, via direct contact and via his actions/statements. Everything he says and does is being analyzed by the Royals' front office. In order to get the contract and the bonus he (or Boras) wants, the Royals must believe Nebraska is a viable option.
Bubba and his folks have publicly stated that there is a strong chance he'll come to Nebraka, and they have set a date for his arrival - today. That sets in motion a chain of events which MUST HAPPEN, or the negotiation benefit of this ploy (if that's what it is) is lost.
Bubba must show up to Nebraska, today or very near today.
Bubba must participate in Fall Camp, and not do it half-assed. He must go full out, as if he's trying to win the starting spot or, failing that, as if he truly means to play football here.
The Royals will not want their multi-million dollar investment, and their top-ten pick, injured in Fall Camp. Therefore they are likely to put restrictions on Bubba's activity in Lincoln.
If Bubba flouts those restrictions, he stands to lose millions in signing bonuses or in salary.
If he does abide by the Royals' restrictions, however, he sends a clear indication that he's likely playing pro ball, again weakening his bargaining position. He also runs the significant risk of alienating Pelini by listening to the Royals rather than Bo.
If he has zero intention of coming to Nebraska at all, the risk to his body physically by participating in Fall Camp is ridiculous. But by committing himself to come here, he must or the ploy fails.
I don't see anything he gains by coming here that the Royals can't easily undermine by setting a few simple rules on his behavior here. His hand is too-easily forced by the Royals simply by choosing to come to Nebraska.
The way I see it, with going off of your statement here is if they put restrictions on him and he decides not to listen to them, they threaten his bonus... all he has to do is keep practicing hard, they can cut his bonus all they want, and he will show them that he is perfectly happy playing Football... the closer Aug. 15th gets.... the more likely they fold to his demands, just to get him there..... or he likes hangin with all his new teammates so much that he stays in Lincoln..... Wishful thinking on my part, but we will see