No your not. Ever have a car salesman make a "promise" while out on the lot just to have it disappear when at "the table"?
If you sign off on it, who's the bigger fool? The goobermint made a Contract, but as usual, prove right out in front of everyone, they had no intent on standing behind it. That said, you could shut the whole mess down tomorrow (goobermint), and my life would not be impacted. Blackbird.
At that point the deal isn't done, and you can still back out. With folks that employ those tactics, it's a good idea.
But if you're promised something as a condition of the agreement, even verbally (assuming you can prove it), and the agent's boss tries to welsh on it later, they'll lose.