It's a convoluted piece of logic, to be sure. Apparently the BCCI has seen fit to tell Indian players not to play for any teams that have ICL players in them:

"The BCCI has advised its players to stay away from counties that have ICL players," board secretary Niranjan Shah told Mumbai's Mid Day tabloid on Friday.

"We are not saying that no player can play county cricket in the future. The England and Wales Cricket Board is coming out with a policy regarding ICL within a year. So, we will see how it goes," Shah added.

There's the restraint of trade angle to all of this, of course, but most of all the degrees of separation aspect is extraordinary:

So you play for the ICL, then travel to England and play for Notts, then VVS Laxman can’t sign up for Notts. You go to Aberdeen for a vacation, and Rahul Dravid can’t vacation in Scotland for the rest of his life. You book in to a British Airways flight to go to England to watch the British Grand Prix at Silverstone, and you’ve denied Sachin Tendulkar the opportunity to meet Lewis Hamilton.

As Geetha Krishnan suggests, there's more than a hint of the contamination logic of caste here. The ICL's route forward is obvious: get their players into as many different teams around the world as they possibly can and make it impossible for a BCCI-sanctioned player to play anywhere at all... Hah!