Quoted from Pinballmike217:
Just because a few diodes broke doesn't mean they all will. I'm sure Stern will will give you a new diode if you would prefer installing that. I'm also sure Stern is now installing an upgraded diode moving forward to prevent the possibility of having this happen again. Stern simply addressed a problem as they should. It is your choice not to install the zip tie if you so choose. Considering the amount of time most collectors spend cleaning, waxing, and upgrading their machines I can't see that taking two minutes to secure a diode is a hardship or the need to bash Stern for acknowledging an issue and taking steps to prevent further issues. Thanks to the OP for sharing this update.
If only a "few" diodes broke I doubt there would be a service bulletin about it.