As indicated by my earlier comments, I approach this from a character construction perspective. The rules should do a good job at distinguishing Haleys from Durkons.
You should never roll if the act is trivial. You don't roll to drive to work in the morning -- although the drivers here make it more Mad Max-esque than it should be -- or to haggle if you're just paying the market price. Trivial generally equals no drama associated with it or any ordinary person could handle it.
Walking across a tightrope isn't definitionally trivial, though. It's only trivial for people with the right skills. A take 10 mechanic is fine for that sort of thing, I have just been arguing that it needs to be paired with transparent DCs. Otherwise a player (and a DM for that matter) doesn't know how to build a character who can easily walk across tightropes (high enough ranks, skill mastery, etc.).
In practice, taking 10 in 3.5 seems to work out just fine. If we're just talking about crossing a tightrope when there is no stress and time, then Haley can take 10. No problem, no drama, she's good at tightrope walking. If there are arrows wizzing by, then she has to roll, and then the ranks really matter (needing to roll a 5 to succeed is a lot different than a 9 in those instances), or there are things like Skill Mastery that say "I'm so good I can't be rattled with these skills." Skill Mastery is unfortunately kind of a pain to get -- M&M does this better by making it more readily available. Batman only risks failing Stealth checks in exceptional cases.
EDITed b/c I apparently can't read.
