I invite the shooter to the start area then give the commands, IF the shooter is already in the start position and I have to say anything other than the range commands I ask them to step out or tell them we are not starting. Either way motosaipens has it right we need to talk to move things along and make things safe, it boils down to where the shooter is when we are speaking that can cause us problems.
No don't change your pre-shot routine just be aware of what is said.