Very early to my connecting in BOS flying B6 last holiday season, flight prior has finished boarding when I observed a gate supervisor receive a phone call requesting what OP is asking about here: someone at another inbound gate asking for a hold due to late arrival so some guests can make it to this one.

Supervisor is conflicted, but in the spirit of the season decides to hold. 5 minutes go by, 10 minutes go by, and just about 15 minutes prior an older gentleman comes up. It’s him, but his wife just had to use the bathroom, she’ll be right there.

Cue additional waiting. 5 more minutes and a cell phone call: “oh she just had to buy a drink, there wasn’t any service on the inbound”. 10 min: gentlemen says he’ll go get her. 15 min: now supervisor is running around the terminal near the gate looking for the guy.

Finally, at 20 minutes supervisor storms back and closes the flight. Overhear him tell the gate agents that the wife did stop to get a drink…by going landside!!! No good deed goes unpunished, and now that flight left 35 minutes delayed with no additional pax.

This story may frustrate those in OP’s position, as of course they’ll run to the gate, but the gate agents have no way of knowing how fast anyone is able to run, whether they’ll get lost, have to use the loo, or maybe have bags that won’t fit and require them to reopen the hold, etc etc. Then someone else’s flight downstream is delayed.

Better to just stick to the policy. Not at the gate at the requisite time? Can’t go…