Actually, there are supports that are blind screwed from the back side. They've been up and running for 15 years...
The side supports eliminated front to back movement on the quad rack but I've put them on all racks now...
On a side note, I once built a 12 foot extension on a covered garage. I used one deck screw to temporarily secure it and square things up, then a storm blew a large tree over during the night with the full force and weight landing directly on the extension. That one screw held thousands of pounds of decking and tree, not to mention the initial impact. You's be surprised how strong deck screws are, lol... (although I do not suggest trying this at home ;) )
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