If your riding will keep you near home, you could take 'em down to the barest rubber.
However, most of us use the bike for 100+ rides and that would not be best.
Another take:
Since you are at the wear bars AND you know that - it's time to replace them.
You would be kicking yourself if you had a blowout after knowing that your tires were "technically" worn out.
It's your comfort level.
If I had a small trailer ready to pick me up, and I wasn't scared of a blowout ruining my bike, I would intentionally ride them down.
But I don't, and I am scared of a blowout ruining my bike - saw a pic yesterday of a rear tire blowout basically removing most of the ass end of a B.
Risk management - comes in all shapes and sizes.
What's in your wallet? Lol.
Cheers,
Steve