Speak up if you are on the jump seat.

Be respectful, but be heard.

Most pilots I fly with will respond back with either continue, or Go-around.

One dot high will definitely put you out of the TDZ, but on a clear VFR day with plenty of runway there is a possibility that the CA will announce continue. Is it "stable"? No. Is it unsafe? No. I don't like the engines unspooled, but depending on the circumstances it may be a debrief item. And, yes you should participate in the debrief.

High and fast: speak up
Low and slow: speak up
Crew lost SA: speak up
unheard radio transmission: speak up
missing a taxiway: speak up
traffic to follow, or traffic in sight: speak up

It's a free set of extra eyes and ears. I think it's just great insurance. In a complex approach, I usually brief the jump-seater about stuff to watch for. I also point out MEL's, or anything that may need to be ignored or silenced on the take-off due to inoperative stuff to prevent an unnecessary reject.

If the crew is flying into an unfamiliar airport and you are very familiar with it, feel free to point out "gotcha's" to the airport or the airspace and any "hot spots" that aren't pointed out or briefed. I love local knowledge and appreciate the education.