Ok, so if:
A) trap detection requires perception + 2 * trapping > trap_visibility + trap_distance + eye_encumbrance_penalty
B) trap_visibility for the worst traps considered (buried landmines, sinkholes) is 10
C) eye_encumbrance_penalty of 2 is fairly common both early and mid game (maybe more late game)
Are we then aiming for Perception + 2 * Trapping = 13 for trap safety?
For very early safety, with Trapping trained to just 1, you then need a Perception of 11, or 9 if you just keep your eyes unencumbered for the time being.
But once you manage to finish training with bear traps you should be at Trapping 3, at which point you only need a Perception of 7 for trap safety.
Of course, your Perception can be penalized by various conditions, which could leave you more vulnerable.
Thoughts? Corrections?