Though that may work for flukes. A fish wish irritants such as ich or velvet will not have anything jump off. They will remain a d infect your DT.
The best method would be to do TTM for how ever long it's supposed to be. Mj tank has seen everything from stray voltage to red slime to ich and flukes and many in between. I know MJ and he does what he believes is best or works for him.
His methods are not for everyone.
I've done on all time QT systems and I also have a diff way of introducing fish.
The point is 98 percent of the members here don't QT
An old school fish vender once told me not to purchase fish during summer and srping because that's when it's the hottest and the fish are at a higher stress during shipping and with disease.
Fall and winter are good times to make personal orders as well