Yes, and it isn't just bitcoin that does this. Two very recent coins also did this. Ethereum classic forked giving holders free callisto coins in March 2018, and Litecoin forked over the last couple of days giving users free Litecoin Cash.
Now you know why Litecoin's price has gone up to an all time high as users buy loads of coins to take advantage of the free ones.
If you remember from the beer money forum thread about getting an airdrop of over $800 worth of eBitcoins (eBTC), those coins also announced a free airdrop based on them going into partnership with Proxytoken. As a result of this I will be given ePRXY tokens on a one to one basis for the 2457 eBTC I already own, so I will get 2457 ePRoxy tokens on 28th February 2018.
With Bitcoin however you don't need to own a full bitcoin to get a forked coin, if you only had half a bitcoin you would have got half a bitcoin cash...Even if you only held 1 satoshi of bitcoin you would have claimed 1 satoshi of bitcoin cash.
I wish I would have been able to have taken advantage of the deal back then, but I only arrived late to the deal