Our A-frame units depend on the roof/sidewall latches to hold the unit together in high winds. The first camping trip in our A128 included a 36-hour windstorm with gusts to near or over 50 mph. Needless to say, it gave me lots of opportunity to think about what our security depended on. I came up with the idea shown in the photos: using a $13 Harbor Freight cargo bar as a supplementary sidewall support. Since then we've endured two more gales in the camper with a lot less worrying about structural integrity.
The cargo bar (2-in-1 Support/Cargo Bar
) is adjustable and the flat plates on the ends pop off to expose two ball-shaped ends that fit perfectly into the rubber grommets at the sidewall peaks. Put it up, give the handle a couple of squeezes (not too tight, though), and the sidewall latches are a lot less likely to pop out in a high wind. Bonus: your sidewall weatherstripping is compressed a bit better than usual, cutting off air leaks. Second bonus: use it to hold your pickup or van cargo in place while driving to the campground. Third bonus: use it as a push-up handle when you need extra tallness lifting the roofs.
I thought I'd invented this idea myself but it turns out A-Liner and Chalet owners have also invented ways to do the same thing, though IMHO not as neatly as this. A-Liner and Chalet companies have also developed a High Wind Kit to hold the roof parts locked together. I'll probably be making my own adaptation of that too.