So, I was riding my '77 Gold Wing down the highway, and got passed by a semi going the other way, and was nearly blown off the road. I wonder, what would happen if I was walking a tightrope, and a gust of wind came up? Is it your position that a character can be so good at balance that a sudden cross wind couldn't dislodge them from a rope? I've seen people get blown off walls, walking a 3 1/2 in. wide "tightrope". I wonder how they would have faired on a 3/8 in. rope?
If they fell off, then 1d20+their acrobatics bonus must have been less than the DC of staying on, considering the wind and the rope width and any other factors.
If they had an acrobatics bonus of +15 (+5 Dex, expertise with a PB of +5 for an additional+10), then it would be impossible for them to have fallen off any rope with a DC of less than 16 because they are simply too skilled to fail at such a (for them) simple task. A "1" on the d20 might mean they wobble a lot, but they'd stay on.
You also can't directly translate D&D to real-world. High level D&D characters are god-like heroes. I doubt you've met anyone IRL with an acrobatics bonus of +15.