I take it you mean is it impossible to bracket?
HFT is a thinking man's sport - sometimes it's not appropriate or even necessary to bracket a target other times it can be very useful. The skill comes in knowing when to and when not to.. also knowing when targets are likely to be bracketing traps and when they aren't.
As an example - almost every event has 4 x 15mm kill targets - these killzones are very rarely doctored because doctoring them would mean increasing the size of the kill. So bracketing 15mm killzones can be a very reliable and accurate method on the minikills.