[Harry Mitchell] “So how can I make sure the event is starting exactly on the the frame boundary if quantization has been turned off…”
Zoom in pretty close to the end of an event on your timeline. Place your cursor at what you think is the end of the event. Use the left and right arrow keys to go back one frame and then forward one frame. If the cursor ends at the end of the event, you’re OK. If it doesn’t, go back one frame and drag the end of the event back to the cursor. Repeat this procedure for all problem events.
HINT: place the cursor at the beginning of the first event and use the numeric 9 key to move to forward to the end of the event (numeric 7 key moves back to the beginning of the event). Use the left and right arrow keys as explained above to ensure that the cursor is stopping on a frame. If it doesn’t, repeat the above procedure.
Press the numeric 9 key to jump to the beginning of the next event.
Repeat as necessary.
NOTE: If you have events on more than one track, you’ll have to do this for all events on each track.
[Harry Mitchell] “why not just leave it on if it’s supposed to make sure all events start and end on a frame boundary?”
That’s the way you’re supposed to edit.
To repeat what John said in the post above yours: “You should always edit video with Quantize to Frames turned ON.”