Never ever put a plug in your livewell overflow drain no matter how much you want provide the most favorable environment for your catch or bait on or off the trailer for however how short amount of time.

It is likely you wont remember the plug is in until you pump enough water into the boat that your get feet get wet.

When your feet get wet don't jump into the water to check your bilge plug.
It is not the bilge pump you hear running it is your live well pump and you can't turn that off while in the water.

Once you have gotten pretty good at remembering the above you can rig up something to keep things like shinners from clogging up your livewell overflow causing the same problems.

I never have sunken by boat by doing any of the above but it has definitely put me into emergency mode.
I do know a fellow you was beached and a shinner got stuck in the drain and sunk his boat one night while camping.