If you use the correct rules you should be OK. You will have a problem if you use a rule that is too thin - because you run the risk of cutting your hand or fingers. Also, get a rotary cutter that automatically retracts when you have no pressure on it - Kai cutters are an example. This will minimise the danger of accidentally cutting yourself. If you make sure you keep your hands behind the tool and cut away from yourself, you have less risk.