As a customer, if I saw this, I’d laugh and walk away.

What you’re doing at your place and what georgiadogs is talking about are two different operations with different customers and different expectations.  If I was expecting a 1/2 pound pub burger cooked medium rare to order, you’re right, this method is unacceptable.  For a high volume, fast food oriented place, where speed and price are often a greater concern to the customer, this method works just fine.
 
Buddy