My criticism was directed at the link, not at you. Mixing your own is a good option and one of the ones I mentioned.

The link specifically instructs the reader to train themselves to drink whatever will be offered at their event. Which means (1) buying some of it themselves, (2) drinking a lot of it in a probably futile attempt to make their gut tolerate something it just won't tolerate, and (3) consuming it at the event.

Maybe I'm just extra sensitive to viral marketing and product placement. But I can't see why a nutritionist would advise athletes to drink something that they know makes them sick, unless it was at the urging of a sponsor.