Well why not? I mean, those who are sufficiently patriotic won't take up the offer anyway and those who aren't should be able to maximise their earning potential and play at the top level if they can. This whole 'they should play for their country of birth' ignores reality; some players who are good enough won't get to and why should guys who want a career in sport be denied a living from it because of some parochial fever? Playing state cricket pays okay but it's risky; if you have a career-threatening knee injury, suddenly the last 10 years you've devoted to cricket (and not in, say, getting a degree) looks wasted.
I mean, the obvious example is someone like Kevin Pietersen. Here's a bloke who, for many reasons, couldn't get a go in SA and moved to England. If he'd been forced to play in SA, for all we know, he could still be playing provincial cricket and not picked for the Test side because his personality is a little brash. How stupid would that be? Don't say it wouldn't happen because I notice a lot of the players from SA playing in England are those who don't quite fit the conservative little mould expected of SA cricketers and could possibly be why they moved.
How about Brad Haddin? Because Gilchrist is in the side and not going anywhere, by the time he's in with a shot for a Test spot, he'll be well into his 30's and probably won't get a show because of that. I mean, no matter how well he plays, no matter how many catches he grabs or runs he scores, he will not get a Test spot until Gilchrist retires. There are countless other examples of players who have barely played any Test cricket for reasons other than their ability like Martin Love, Darren Lehmann, Jamie Cox, David Hussey, Brad Hodge, etc. and that's just in Australia where they at least get paid reasonably well. How many players in other countries are there who even gave up on FC cricket because it was too risky? I'm sure most of us have stories of guys who were good enough to at least play for their state/province but chose another track. Would Lou Vincent have even played Test cricket for Australia? Yet in moving to NZ, he's played 22 Tests and 97 ODI's and will likely play more.
I just think it's amazing how we have several threads on CW Chat here where people lament lost talented players for reasons other than ability yet when an opportunity arises to actually address it, "NO!! It's not traditional!" I bet just about everyone can nominate how many Tests Barry Richards played for SA. Yet how long ago was it? 40 years ago? And we're still talking about it! Instead he languished in English County cricket for the rest of his career. Aww, too bad but that's the luck of the draw. All too easy to say that when it's not you. Graeme Pollock is another who could have played for England if this system came about. Even then, that's not taken as a given; any cricket board would have been interested in a player that good and players like that should be afforded the choice rather than told for the next 30 years "Sorry about that old chum but hard luck."
Deal with reality, people. Cricket is a career choice, not merely a game any more. Who is anyone to deny a career choice for what is a risky enough choice as it is? The fact is, though, it's irrelevant; this is going to happen. 2nd tier players in various countries (especially, I suspect, the WI where regional vagaries as much as ability determine selection) will get the opportunity to jump ship and they should. It's still a big risk anyway because there's no guarantee of selection at the other end but at least they have a chance to be picked on ability than sit behind the incumbent for years and possibly never get a shot.
Even all of the above said, it's not like any of this is new. There are plenty of examples of guys playing in countries other than where they were born. This idea just formalises it and all opposition to it has been emotional thus far. All well and good for you guys who aren't in the position of having to make a tough choice.