Walker doesn't deserve anymore rings!
Really, these players want both the money and the ring. Getting bought out is a little over the top, but if they can get it why not? In some ways, the teams are responsible - if they put the right talent together and pay them so they can assemble all the components, they hold onto decent players. If they can't do that, they should let the player go somewhere where he has a chance to get a ring.
Especially when they're at the end of the career's they should already have enough money that they shouldn't ask for that kind of a bonus.