How does a glide slow anything down?
You don't turn in from the same downwind position as a powered approach.
Agreed five seconds or less does suffice, so no need for the call. It just makes Tower's job more difficult. They're having to make sure the next aircraft isn't too far around base/final to allow the lineup and wondering what the delay is for.
Yeah, I know, it's just a few seconds, so why not just line up like every one else does. If things are tight, Tower will tell you it's for an immediate.
As for advising the student etc, the student should know what to look for before they go out. That's what briefing is for. It's a 172, it isn't that hard.
