That's the main reason I'm going to put a coat of Tremclad over the galvanizing. On our 60 we have a piece of galvanized pipe added to the front of our non-galvanized powdercoated brushguard. It seems to result in very toxic fumes, but it has been welded for sure. Might be influenced by the fact that the bumper, in which these bolts were mounted, was zinc-dipped. Btw, I would include the paint problem in the above listing.
Most painters hate zinced steel, only powder coating does a good job.
Last summer I made some high-rise sprinklers for my wife's vegetable garden which involved welding dipped galvanized components. Also, the galvanizing burns brightly while you're welding, and can somewhat obscure your view of the progress of the bead. Lastly, it seems that the galvanizing can burn lazily once you stop welding. At least the flame is easy to blow out, but have fire extinguishing stuff handy. And on the back-side, too.