My Sweet little Blackmailer

I have only found one thing in the world that bugs Derek - spilled water. This is especially unfortunate for us because with little kids spilled water is about as common at our house as breathing. For some reason this is Derek's pet peeve (Derek's the only person who only has one pet peeve!) - it really pushes Derek's buttons. So this afternoon Tyler is doing homework at the table and I'm setting the table for dinner around him. I grab a cup of water and drop it on the floor. Tyler says, "did you just spill that water?" I say, "yeah, don't tell dad". He answers immediately with, "if you put my put my homework in my backpack for me I won't tell dad." Can you believe it? What a sneaky little guy! I just look at him and say, "I'm not putting your homework away - so go ahead and tell him." It really disappointed him that it backfired so quickly. Should I be worried?