IANYL, though I do something similar for a living.
My answer centers around the agent actually saying what other teams are interested and what prices they are willing pay.
From what I can gather, typically, in these types of deals, an agent has some leeway when it comes to shopping for the best deal for his client. He can bandy about names of potential employers, salary ranges (in reference to the market), etc.
However, there are several rules which the agent must abide by: any rules/limitations in the principal/agent agreement (i.e. the “master agreement” between the athlete and the agent), any rules within the professional sports organization (I personally know that te NBA has to certify agents, other leagues may have similar criteria as well), and any non-disclosure agreements limiting what can be said.
These NDAs and master agreements are usually the only restrictions in the non-sports related contract negotations. Typically, they mention that the price is confidential, and I’ve seen some that say even mentioning the other contracting party is also confidential.
So, to answer your question as to whether one is in violation or not, it depends on what agreements are in place and what the rules of negotiating are in the particularly league.
To answer you other question about “bad faith,” my knowledge on this is pretty rusty:
Bad faith (against the agent) is typically between principal and the agent. These types of allegations usually center around some sort of tortious interference of contract/business (depending on what the relationship is at the time, here I am assuming business, as a contract has yet to be signed) argument/theory. The elements of this tort vary by state, but typically include 1) a business right was interefered with; 2) the interference was wrongful and was not priviliged or excusable; and 3) damage resulted because of the interference
I’m going to skip the analysis/theory of how the agent factors into this, but let it be known that an agent can be subject to such claims (c.f. agents are thought to be an extension of the principal, so arguments can be made that the principal cannot interfere with himsel)
In these type of cases, the agent is acting in bad faith to the interest of the principal with a third party’s contract/agreement with the principal. Bad faith is typically demonstrated by the agent acting in his own best interests, rather than his principal. So to demonstrate a scenario where Boras is acting in bad faith (which I would argue isn’t demonstrated in your scenario): Boras would have to have some side arrangement with a particularly team (for ex. the Cubs or the Tribune Company) that for every player he can have sign with the Cubs for less than X, the team will pay him extra cash.
As a side note, IME, it is poor negotiation tactics to actually tell the person you are trying to sell what the actual price is. The team will have some idea in mind of market value based on the player’s past contract. As an agent, one should try to make the team say what price they want first, then drive the price up from there. The first price is never the best price.