Why would they regret it? They got good production, for less than market value, and then traded him for futures. They got everything they wanted out of the deal.
I don't think there's a problem signing and hometown discount. But if I were going to do the organization a solid and take less money, you bet your ass I'd want a no trade clause. No way would I do them that favor without some insurance for myself.
That was my first thought, if he wouldn't have been traded I have a feeling he wouldn't have regretted taking the discount, or at least he wouldn't have said anything about it.
I would've regretted it too, take less money so you don't have to uproot your family, find new living arrangements, etc just to have them ship you away anyway.