By using Command + Shift + 4 and then pressing space, Mac players can continuously jump up and down without touching the keyboard. Using this short cut while Minecraft is running also causes issues with other aspects of the game

Steps to recreate:

1. Tap space repeatedly
2. Use the MacBook camera shortcut (Command + Shift + 4)
3. Press Spacebar once the Mac camera is open (as indicated by crosshair with coordinates for computer's grids)