There are several things that can work in your favor when you throw the Hail Mary. First, you could complete the pass, which is unlikely but could happen. Second, you could get the PI. As many have pointed out, they've "never" seen a PI called on a Hail Mary... but, this year, we have booth review of PI. I guarantee you, at some point this season, we will see a PI call made on a challenged Hail Mary when it is especially egregious. It just has to happen now that these calls can be reviewed. Third, you could benefit from some other kind of penalty, such as a roughing the passer, which I think we were very close to getting in this particular case.
Now, let's look at the 70 yard field goal. You can find YouTube videos of guys making 70+ yarders in ideal situations with no snap, hold or rush. Heck, you can find video of Justin Tucker making 70 and 75 yarders. People have said he hit the crossbar on an 85 yarder at the Pro Bowl. Yet his career long, when a snap, a hold, and linemen to kick over are factored in, is 61 yards. It's just not a responsible coaching decision under any circumstances.
Any special teams coach will know his kicker's functional range. I coach special teams at the high school level, and while my kickers have nowhere near the range of an NFL kicker, similar principles apply. My two kickers can both make 55 yarders fairly regularly under ideal circumstances using a holder with no snap or linemen involved. But once you move them back to 60 yards, they miss every time... and not just by a yard or two but often wildly because the mechanics have to change once you exceed your range.
