These ones are boom mounted from the factory on the high speed models. Problem is, a lot of guys grab the rod holder and use it to lift the downrigger up after fishing. They're not really designed to do that, lots break, sometimes losing a rod and reel in the process. You're so surprised that your rod holder has broken that you fail to grab your rod and reel as it heads for the deep!
I agree it is not good to use them as a handle, however, it is also tempting for some. The first thing I do with these holders is remove them from the rigger and replace them with very expensive, after market, high end, quality, heavy duty all stainless holders. Use them as a handle all day long if you want.
I just don't trust the Scotty holders much anymore that have the plastic post and/or ratchet head, with the exception of the steel pin Striker which is a different design. Those long Scotty stainless tube type still have the all plastic post and ratchet head or just the ratchet head/mount on the rigger version. There extra length may add leverage. I would be willing to pay more for the riggers if they replaced the small plastic bottom section of the tube rigger holder and mount with quality stainless because then I would not have to replace the entire holder and that design would not add much to the weight.
The only downside to upgrading to the after market quality all stainless holders on the riggers, besides cost and perhaps having to do some very minor modification, is that they make the riggers substantially heavier when you are carrying them or swinging them up and down and that would also add to shipping costs for the manufacturer. I don't think the added weight should be an issue for the Scotty rigger mounts, they seem very strong. We have brought up very heavy crab pots on those mounts.
Once removed from the riggers you can still use the Scotty tube holders. We add a regular plastic Scotty post to it and only use it out the back of the boat as an occasional light weight shallow line. Even then, no Islanders are going in it. If we are stacking we use a regular, shorter all plastic Scotty holder, but again, the Islanders only go in the heavy all stainless rigger mounted holders. I like the Strikers, they are great for Halibut but find them, for me at least, a little awkward for salmon. Perhaps I have just not got use to them.
Scotty is not the only one who has had this issue. I have seen plastic holders break from other manufactures. One had a weak spot where there was a bubble in the plastic and the rod and reel went overboard.