Scoring lines for the Boot stripe

[L124C]

I'm getting ready to paint my hull with two part Polyurethane. Don Casey recommends removing (sanding) the Boot stripe before painting the hull. He suggests scoring the stripe before removal so it can be repainted in the same place. In a picture, he appears to be scoring it with a knife.
Has anyone done this? If so?
I'm assuming he suggests removing it (mine is in good shape) because the Polyurethane will wick under any tape used to mask the boot stripe?
When you score the hull, wouldn't sanding the boot stripe off remove the score (unless you went deep). Somehow, taking a knife to my hull freaks me out a little bit. Kind of silly, but it does.
Anyway, thoughts from anyone who has done it?

[tommays]

I measured from the rub-rail down to waterline every 12" and made a drawing as it was something i did NOT want to lose and the path tends to be funky

By the time you do the priming and topcoat it would be tough for a scribe mark to survive

[Minnewaska]

Of course, this all assumes that nothing has changed the level of your boat since it was last painted. Anchor chain, dinghies, moved or expanded tankage, etc can all change it and you really need to re-shoot it.