Disabling Theft-deterrent on stereo

I have a 99 s10 w/the theft deterrent feature stereo I am worried when i disconnect the battery i will be in trouble.Do i have anything to worry about without knowing the code to enable?

With the key turned off, is there a red light that blinks every now and then on the face of the stereo? Normally the code is not programmed unless someone takes the time to read the manual and do it. If no red light, nothing to worry about.