The Crimson Binome
Hero
I get that, and I get that you're going to have the same range of bonuses to hit (or save DCs for) a party of any level.No, the accuracy will remain the same for 2/3 of the party on average, because no class gets proficiency to more than one of the three major saves (dex, con, wis) before very high levels. A level 20 fighter will be just as likely to pass that dc10 dexterity save as a level 1 fighter, unless he raised his dex or took a feat for it.
I'm just noticing that a deadly trap for a low-level party would be +10 to hit for 4d10 damage, where a setback for a high-level party would be +4 to hit for 4d10 damage. If the DM creates a trap of a particular lethality for a party at one level, it won't cleanly fit into a consistent degree of lethality at another level.
Which is fine. Nothing really needs to be tailored to the party.