I have done the same thing as you by connecting the hose to the inside of the airlock. It's 1/2" ID so it is pretty small. It worked on my second batch, but my third batch got clogged up and blew everywhere. So basically you are taking a risk. I am going to buy a bigger blow off tube before I start my next brew.
"Remember, the only way to really F up your beer is to replace your yeast with ketchup." - NineMilBill
Primary: Victory Hop Devil IPA
Bottled: Delirium Tremens
Bottled: Black Dog Ale