Once users get to know it , they love to the ability to CTRL + = (Replace Field Contents). This works pretty good on flat table layouts since you can see what record set you will be affecting.
But, users are doing it from within Portals as well. As you know, doing this within a portal doesn't change the records you think it will change. It frequently changes tons of records behind the scenes.
So, CTRL+= in portals are deadly.
There's no decent options to restrict certain actions in portals especially this one. I've try setting trigger script to do nothing and capture the keystroke using Get(TriggerKeystroke) but I can't seem to stop it.