If I were in the same situation, and my plane was scheduled to leave the next day, unless I had lots of money, I'd be on that plane. Most young people book non-cancellable flights and try to go for the cheapest flights. Heck, that's one reason Guatemala is popular with tourists.
I have been stranded in that part of the world (40 years ago) and would absolutely hate to have that happen to anyone, ever. Student and special deals (booked early) are as cheap as $250 from LAX to Guatemala City, RT.
It's true that they'd only be out $250 if they rebooked - but they would also have to pay for lodging. If the Yoga Retreat had offered them a few more days of free stay, they had no guarantee they'd already be booked for another flight.
I don't know, but if I was adjacent to (but had not observed) a drowning or mishap while kayaking, my main goal would be to leave the country. It would be panic-inducing to have to change plans (probably miss work at home and possibly miss connections onward and have to spend money on LAX hotels).
The Yoga Retreat knows how to get hold of them - but they appear to have been nowhere near the site of the accident and know nothing except what the one woman said - that one woman is the only valuable witness, IMO.
On a different topic - here's the Kayak Guatemala page for kayak rental
Rent a kayak or stand up paddleboard (SUPs) and explore Lake Atitlan with absolute freedom. We have single, double, and expedition kayaks available..
kayakguatemala.com
Participants are shown without PFD's, but also shown aiding each other with a paddle to get back on a kayak, shown diving from an anchored boat (not from an unanchored kayak) and staying fairly close to shore. However, people who rent their own kayaks simply get a brief orientation to paddling and are free to do what they wish, apparently, once in the kayak.
Sounds like everyone else behaved as shown in the video on that page (last part of the picture set) and stayed close to shore. Whether this particular group had been given guidance on rescuing others is not clear. But the concession itself seems to have at least some emphasis on safety.
It's a tragic accident.
IMO