I see the fans as not helping to keep the fridge working right there and then, but reducing the stress on it so it lives for longer (with most devices involving electricity, the cooler it runs, the longer it lasts).
My fridge does indeed work fine at 40C (highest recorded inside (the van, not the fridge!)) and my previous Weaco hit 50C on a few occasions, but for the reason I gave earlier, I have a fan pointing at the back that comes on at a preset temperature.
Simple Controller like this with a little 12V Fan - when it kicks on, I see the temp reduce rapidly.
PP - Fridge by
David, on Flickr
For a cost of around £15 I think it is worth it, especially for those folk who have invested in excess of £500 on their fridge.