Good to hear from you, Doug!
For me the Pencil Tool already is set that way. However, upon tinkering, I realized that the “S” key is mapped to be both a navigational key, as well as an input key for the Level Sequencer. This means that if I try to move the camera/view down, I could unwittingly be adding a key.
So, I changed the Key quickbind to something else, and now I’m no longer having this issue.
…for now.