Here's the deal, Flight Attendants spend hour after endless hour fielding questions and complaints from passengers. Frankly, I don't know how they do it without going nuts. The problem is, while I respect what they do, F/As are generally the least equipped to answer most of those questions or fix many of the complaints. They spend their time in the little cocoon of the cabin and don't intereact with many of the other deparments or employee groups (ask anyone at an airline and they'll tell you that F/A rumors are always the most useless). 99% of them haven't got a clue about aircraft systems, aviation weather, and they don't memorize the available facilities at the hundreds of airports that we fly into. Unfortunately for them, they are the public face of the airline and therefore have to deal with any number of issues that they don't control.
So, when you hear another PAX say:
"Can you call ahead and have them hold my connecting flight"
"Can you have these miles added to my frequent flier account"
"What are we flying over right now"
"Did my bag make it on this flight"
"What baggage carousel can I get my luggage at"
"What is the weather like in Chicago"
"How long is it going to take to fix the hydraulic problem"
"Why don't you serve Pepsi instead of Coke"
"Can you warm up the floor area, my feet are cold"
What the F/A wants to do for most of these requests is say: "I have no freakin' idea".....but what she will probably do is smile nicely and say "I'll see what we can do"....and then continue on with her day. In the particular case of holding a connection, the F/A has no way of contacting Dispatch/Local Ops on their own (though I'd be interested in the 2 or 3 that you know of). "If" they actually do let the pilots know, then the pilots "might" send it downline via ACARs or Company Radio if, as snydersnapshots mentioned above, it is an unusual case. I can assure you that someone having a tight conection because they wanted to save themselves $9 on their ticket doesn't qualify as a special case.....that's half the airplane. And if it's past Top of Descent, sorry, I have other more important things to deal with and Flight Ops management considers that a 'nonessential duty'.
I'm not disrespecting F/As here...they have a tough job. I'm simply telling you that passengers bombard them with questions and issues that they have no knowledge or ability to deal with. (BTW, the same goes for the gate agent....people will continually pester them with questions about maintenance and weather delays and the Gate Agent hasn't got a clue. They look down at their computer and recite to you what it says in the flight history....it's like going to a fancy restaurant and asking the car valet about the Menu Specials)
I'm surprised that the OP was able to book a 25 minute connection. Most airlines have minimum connections times that vary by airport to take into account the compexity of the terminals and the possibility of International travel. Good for him if he was able to save some money on the ticket, but please don't encourage that type of risky travel by saying "There's a good chance the Flight Attendant will get them to hold the connection for you" because that's wishful thinking.