That's a strange way to negotiate. If a rival came to me with an offer below my current salary I'd tell them to get stuffed. There's no need to drive to his house with a truckload of cash but offering a 25% pay cut is just an insult and would likely make it harder to negotiate down the track.
Of course that's assuming we actually did offer 300k in the first place.
I can see it that way sure, and if you know he is on 400k then 300k is a borderline slap but i would imagine the conversation with his manager was more along the lines of:
Manager: Thanks for your interest, what salary are you looking at for Kurt?
Broncos: We are in the 300's as well as offering some of the best marketing and self promotion opportunities in the NRL through our media exposure vs. the Panthers.
Manager: Well he is already on 400k so...
Broncos: OK, before we sharpen our pencil is Kurt even interested if we go back and look at what we can offer?...
This is vs. the Paul White method of:
Manager: Thanks for your interest, what salary are you looking at for Kurt?
Paul White: We would like to offer him 600k a year for 3 years, he did just play Origin after all!!!!
Manager: Hmm, he is pretty happy at Penrith, is that all you can do?
Paul White: I can add on an extra 2 years as a player option in his favour
Manger: Done deal
A few things to remember, its not Kurt direct, it's all through his manager so a low ball offer is not as personable an insult as it may seem and also, it's just Kurt Capewell, it would be a different approach if it was Cameron Munster.