The whole comment is good advice and I think most people are fair about it. I remember this part above specifically from a convention I played in 30+ years ago when I was a middle-schooler. The table had one older person than us and he kept saying the tactical thing all of our PCs would do instead of asking us to do it or letting us play the way we wanted. He would tell the DM that the thief will sneak around back and the mage will cast such and such. Not sure if he was trying to make the convention game fit in the allotted time or if he felt the 'kids' could not play, but it always stuck with me. I remember telling the DM that my PC was not doing what he said and that I was going to do something else. The DM seemed to catch on and then asked everyone what they were doing and things went fine from what I remember.
Which I agree with. I play with new players and will offer advice, but also let them know that when/if it gets annoying to let me know. In addition, we do discuss tactics during play at times.
But there's a big gap between offering advice and discussing options and telling people what to do.