It's not much of a "negotiation" when the power imbalance is such that the employer can say no to your every request, but if you say no to any of theirs, you're unemployed.

Not only unemployed, but potentially unemployed in a new city, and liable for returning the relocation package. There is zero leverage in such a position if a company alters the deal, and tells you to pray they don't alter it further. Thankfully that that didn't happen to me, but it was in the back of my mind that after moving, I wasn't in the greatest of positions if there were to be any objectionable clauses.

It's especially not much of a negotiation if they fire you for daring to negotiate, rather than saying "no".