Interesting. And creative idea!

Personally, I wouldn't like these adhesive nubs because -- outside of tournaments -- I think that deathsaves are awesome. Similar to @85vett, as long as someone isn't kicking the legs or bashing adjacent cabinets, people are free to deathsave on the pins in my collection. I have my tilts set pretty tight, that even a smooth deathsave will usually get you two warnings on default debounce settings. On a rare occasion, you'll only get one. So it's similar to the ability to do a massive slide save for SDTM or wicked shimmy: if you haven't used up your dangers, then you can attempt to save the ball by making a big move.

We even have a group started locally here called Death Save Disciples (DSD for short), along with a sweet sweet T-shirt showing the grim reaper trying to take your ball in a R outlane drain situation.

Nah... it's like riding a bike.

I still remember the first major tourney I went to, seeing you play for the first time, and marveling at how good you were at nudging the pin -- and how much I had to learn.

In competition, a death save is a DQ, regardless of whether you're in single ball or multiball play. Enforcing it could be more difficult, as you suggested, since a player could be nudging simultaneously to influence balls still in play. It comes down to sportsmanship. Like some of the other infrequently encountered rules in pinball comps, if the potential infraction can't be assessed with certainty, then as a TD, I would ask the player, "Did you nudge it to try to death save the outlane-drained ball?" If yes, then DQ. If no, then play on... and I'm then watching the player's remaining ball or game to ensure there aren't any other gray areas that he/she is attempting to circumvent.