With all due respect, Curious, part of your JOB is, "parading to the center of the field to talk to captains - who aren't listening to anything you say anyway - and ask them what I already know". How YOU deal with what responses you hear, what precautions you elect to take to avoid any and all possible confusion and/or miscommunications is prudent and rational, as long as they're acceptable in your area, and are likely a contributing factor as to how much (or preferably how little), "clean-up - too many f@#*-ups to trust ANY decision to a player" YOU may have to deal with.
There have been multiple, SOLID, suggestions about avoiding such instances included in this discussion. As is USUALLY the case, what MATTERS is what WORKS and is ACCEPTABLE in YOUR area, which may be somewhat different from what is rountinely done elsewhere.