virtualbox.org

Is it possible to change the reset shortcut from Host+R to something else? Or get rid of the keyboard shortcut?

I am so habituated to Command-R for reload page in a web browser (and I use VBox on a Mac for web site testing) that I hit Host-R by mistake very often.

Try changing the host key to something else besides the ctrl key.
VBox GUI file -> preferences -> input. Click in the box and then hit the key you want to use.