We've never had a drawer come open (even on off-highway washboard roads), and our E450's rear springs were really stiff under our small Class C before we changed out the stock rear shocks.
All our drawers came from Winnebago with what I call "gravity locks" on them. Each drawer slider has a notch in the end that rests in a portrusion at the front of the drawer slider's channel, kept in place by the weight of the drawer. You have to lift the front of each drawer straight up about 1/8 inch and then pull it out. This simple approach has proved to be failure-proof so far.
Do any of you have this same setup for latching your RV's drawers?
However we have had some doors come open - until I added double magnets on them to replace the single magnets that they came with.