Ovinomancer
No flips for you!
And this is a good practice, one that you have instated without the direction or support of the rules. That it seems fair and obvious to you is a credit to you, not the rules. The rules of 5e don't even mention this as a preference -- they just say the GM narrates the result. ISo ... heterogeneity and all-a-that, but if I'm DMing and it's not clear what result you want, I'll ask. If what you want isn't consistent with what's come before, we'll negotiate. If it's as sketched-out as your thumbnail above, I'd literally let you choose the result.
This connects up to a different trend I dislike, which is telling me my character is awesome when in practice they aren't. Different thing. In your case, it's a failure to imagine a way for a competent person to fail (and if it's that difficult, maybe the check isn't necessary?).
The extensive evidence present in the printed adventures for 5e, which often recommend hiding results from players until after an action, regardless of result on the check called for, shows that instead it's you that's the outlier here. That you're the one defending the rules for doing something they don't even mention is the strange thing.It is entirely plausible they believed they didn't need to say do, because they wanted to believe they didn't need to.
I like 5e. I'm just very honest about what it is. When I run 5e, it's up to me to provide the necessary feel at the table -- the rules don't do much to support me, they just let me do whatever and call it 5e. Outside of combat, that is, which is pretty solidly detailed out. And, to be frank, my group plays 5e primarily because they like the tactical combat engine, and I can make the rest of it work out well enough (by being very explicit about DCs, risks, and rewards prior to rolls). The combat I credit to 5e, the rest... well, they told me it's up to me when they said rulings not rules. I struggle why this is even an argument, what with the sales pitch being exactly what's in the tin.