I'd consider it a mistake on any dirt or potholed road when doing long distances. But if riding like a retired pensioner, then you can do with ANY boxes setup w/o anything braking.

I had Givi plastics (a bit older models, but the mounting system seems to stay same for them, only outer design is updated) on my Susuki GSX bike, even here in Estonia, mostly on very shaky USSR style paved roads I nearly killed the plastic mounting points (where metal frame meets with the plastic box), sold them. If i'd take it to out gravel roads, they'd certanly fell off at one point taking all the pot holes

Givi pannier frame twice broke because of vibrations, first on our bad roads and again it managed to broke less than 12,000km on one of my tours on a nice european roads. Needed to re-weld it twice. Can't imagine if I fit the same system on my trusty BMW GS that ride very hard on dirt and gravel, at one point I'd probably see they're missing from the bike.

My Suzuki had amazingly lot of electrical and some mechanical problems per little 50,000km I rode with it, I whish Suzuki gave me a new bike every 10,000km or so, even more problems than the plain italian boxes created per that distance, but still, I'd recommend eighter soft or alloy boxes solution if you want to ride the bike hard and/or load the panniers hard.

In fact I've seen older Givis (with those absolete outer shapes) and they had more robust fixing system than the new ones, visually seemed to be better. But still I think indeed you can use plastics panniers like new Givis, if riding very carefully, slowly over potholes, not loading them hard, then you'll have no problems on what ever boxes you have and can praise the boxes sky-high after coming back from the trip. As always it's up to the rider.

Another thing is "crash-proof" question that most of people don't consider, fortunately or unfortunately. Solid "bending and un-cracking" alloy or a soft (textile) panniers don't fell off even on high speed crash, they have a material deformation "reserve" compared to plastics. In Poland I've done a approx 100kph crash after a car decided to do an illegal maneuver. Bike slided more than 10m on tar first, off the road the over 300kg fully loaded bike did 2 saltos together with us. Thick 2.5mm boxes stayed on till the end (VERY strong frame and very strong mountings), boxer cylinders had protected my legs (i.e. with inline or V-configuarion bike my leg bones probably had been into multiple pieces) and alu had boxes protected my g/f's legs. Basically in combination with cylinders they created a "protective space" for our legs. From the situation, I can easily tell that if we had plastic boxes, my pillon's legs would have been damaged, and other worst things happenined I don't want to imagine.

Pic of the aftermath:


See those boxes and now replace the thick 2.5mm aluminium with any comercially available plastic box that is mounted on the bike with fragile frame. What would have happened to my and her legs then?

In my definition after being through this: plastic boxes would have been simply "vaporized" with these kind of forces.

More about it here: Caja Sahel

Most of us think it's mostly our own faults doing crashes etc, but this story proves you must be careful of other mad cage drivers that can end your travel in a very unexpected moment. Choosing correct boxes can play a crucial part for your own security and protecting your bike too.

Ride safe, Margus