You really don't have to worry about accidentally building too much muscle. It takes a ridiculous effort. I'm talking about multiple hours of training a day, 6 days a week. If you go and spend an hour in the gym lifting weights 3x a week and do some cardio before each session, you'll get a nicely shaped body with well defined muscles but you definitely aren't going to be even close to looking like Ronnie Coleman, trust me.
With "eat up" I was talking about losing muscle by not doing any exercise while I'm on a caloric deficit :)
Make sure you're getting enough protein and do some weight training while you're cutting and you shouldn't really lose much, if any, muscle.