Warning about using anything other than the acyrilic ruler.
The only time I ever cut myself (was just a little shaving of the top skin on my finger) was when I needed to quickly cut an additional strip. I couldn't find my regular 6"x24" ruler so I grabbed the metal 2" wide 48" rule from the hardware store. I was accustomed to holding my hands a certain way on the 6x24 and wasn't paying attention to the smaller space on the metal......you guessed it.....
Fortunately was not serious. So the warning is that when you use something that you are not accustomed to, take care how you hold it and place your hands.