Rugby 101 - Know your rucks from your mauls!

This is explicitly covered in law by 8.20.

Side note, you said 90 seconds. That's a conversion. A penalty is 60 seconds.

Anyway,

Like all laws in rugby, it's open to interpretation what the referee considers 'a kick at goal'. Referees aren't mindless machines, and in the case of a match with only a few seconds left, I think most referees would see through this and award a scrum to the opposition team.

The same applies at a restart kick. You can't just kick the ball out of play or not ten, thinking it'll cause a scrum and the match will be over. Or at a lineout, if time expires in between when the ball went out and when the throw is taken. A team that wants the game to end could throw the ball crooked on purpose to cause a scrum. But the scrum will still take place, even though time is up for exactly this reason.

The sanction here is a scrum, not a penalty. Here's a video of it happening in a ProD2 match.

https://www.youtube.com/watch?v=yxW2xyMVJTY

The story I've heard is that ever since Italy ended up down to 13 because of a red card and an injury to a hooker, Ireland have been listing their front rows as being able to play all possible positions they're in any way capable of playing, just in case.

I don't know if every prop can drop in at hooker though at a high level. I've seen the official forms from all provinces over the last season or two and they aren't listing all front rows as LH, TH, H capable. Likewise they're not listing all props as TH/LH. There are still definitely specialists in all positions. I think they're just more likely to list it down if someone does have some experience.

I personally though this was strange too. But I was doing something else while watching and didn't get a good luck at Lowe while he kicked. Was he under pressure from a defender?

If the player gets a chance to kick the ball, and isn't under severe pressure, that's advantage over for me.

If the player snatches at a kick under pressure and makes a hames of it, I'd bring it back for a scrum.

Law 7.1.a says that advantage "May be tactical. The non-offending team is free to play the ball as they wish.". Kicking while not under pressure would come under that definition for me.

This was never a problem until they added the shot clock. They wanted to clarify things because some players like Sexton used to take quite a while. 89 seconds feels like a very long time when you can't see a shot clock so the crowd start jeering the player, even though he's within his time.

But what happened was that now players know exactly how much time they can take and so every player is taking every second they can. So it's actually made the delay worse. They traded a minor problem for a bigger one.