Being in IT, I know that messing around with code you don't know, or fully understand, can lead to all sorts of unforeseen problems. I suspect that genetic code is no different, but the consequences could be much more dire.
I mean, look at how much trouble Micro$oft has keeping Winders secure, functional & disease free.
You're right. Genetic code is no different. Don't go messing in the kitchen, if you don't know what you're doing.