Perhaps the sole programmer was under the gun to get the code out the door. What is easier to do - write one line of code to restrict everone or sit and think about all the situations where where the program should be would not impact the situation? In the old days, you just determined the number of inventory units affected and then write a JE (if you remembered to do so). While I liked the thought, the approach taken is too unwieldly to implement. Again, we are bitten in the butt by unintended consequences.............
Personally, I think every Sage engineer (better yet MANAGER) should work in the field for a period of time so that they actually undestand how people use the system.