[golfdesigner]

As L I try to make one last glance to partners and table before bouncing ball to thrower, then I know if player is at table to come in, if I'm T same thing, quick look at table to see if all is okay and they are not waving frantically for some reason, then you see sub waiting to come in. If sub is at table and has reported to scorer, then I whistle as soon as ball is thru net. Then bring in sub and show in-bounder they can run baseline if needed.
Most times on spot throw-in I point to spot & tell in-bounder that they're on a spot, if they have baseline I tell them I'm starting you here, but you can run the baseline if you want to...then signal they can run..That way all know what he can and can't do..

Just my $0.02 worth.