Weird. I mean, that's economically irrational. The call buyer should always, always, always execute the option if the strike price is below the aftermarket Friday price for which they can sell the stock, and collect the difference in price as an arbitrage gain. There is *never* any reason not to do this.
And the kicker -- the brokerages will actually *do it for you automatically* if you don't issue special instructions. On Saturday, they will execute options which were in-the-money on Friday close if you don't give specific instructions to the contrary. It's actually an options exchange *requirement* that they do so.
This implies to me that a lot of call buyers are even stupider than I thought they were. Making specific phone calls in order to avoid execution of options so that they can unnecessarily lose money?!?
Perhaps they're all wildly leveraged and can't actually afford to buy the stock (and sell it in the aftermarket)? But that would also imply wild stupidity on the part of the call buyers.