I mounted my wire looms to the ROPS by drilling (yes!) 3/16" holes, and tapping for #10-32 machine screws, then using cable clamps. I think small holes are less of a concern than larger ones. Plus, I wouldn't want water to get inside the ROPS.
Agreed. I used black tape to hold my wire for now. I think I'll drill & tap, with
zipties with mounting hole! Thanks for the mention of tapping, that's clean. Theres other ways too, the
Ziptie saddle mount (for .25" wire bundle). I've used the adhesive mounts, sometimes they just come off, I don't think they are for outdoor use and they only stick to the materials they LIKE (for long periods). I guess a guy could JBweld nuts onto the ROPS (no drill).
If little holes in the ROPS increase danger, then could weld up all the un-used (large) holes in the tractor main frame to increase safety. It could be like cap & trade. You get to drill 5 little holes in the ROPS if you weld up one big hole in the frame. Sorry, Hogwash alert.

Your tractor should work for you, not you for it. Except where you ENJOY working for it. Or being a rebel. Man that's some stick-it-to-the-man! :laughing:
If you want lights, the ROPS is the OBVIOUS location, so drill some little holes (IMHO). And when people say "aren't you worried about the ROPS? Say "YES I am, if the tractor tips over I hope to keep inside the safety zone". And you can add "honestly I'm more worried about reversing over an embankment so I added better lights".