I've seen this come up a few times, and figured I'd probably go ahead and cover it.
Maille contains small parts. If essence, Maille is small parts, alot of them. If your child is prone to chewing on things, regardless of their age. Maille is not exactly a wise choice for multiple reasons. The off chance a ring comes loose and becomes a choking hazard being one of them.
Speaking of chewing on things, there are also CPSA standards to consider. Most of us who are marketing our craft can do a few things to stay in compliance. The first, is to use materials on their known safe list. At last check, items composed of these materials did not require manufacturer (that's you) testing. Be sure to stay up to date though, and not just take my word for it. Your suppliers should also be able to tell you if items you're purchasing from them are CPSA compliant. The next point to mention, which brings everything back on topic, is not to market your product to children under 13 in the first place. This is the safer, smarter, and simpler solution.
Now, if you have children, little gamers or squires or Hallowe'en knights, and they want maille, that's your decision to make. Keep a few extra things in mind: Young little bones are not fully formed, and adding a sudden extra weight load could end up causing some frightening damage. Also, the black oxide rub-off from standard aluminium, and the zinc coating on galvanized steel, are probably not something you want ingested. Zinc fumes are certainly toxic (one reason you should never heat galvy) and I wouldn't personally take the risk in any other form. A good solution to both of these problems, is the use of Bright Aluminium. Properly called alloy 5356. It's lightweight, doesn't leave that dirty looking black junk on skin and clothes, and it's incredibly shiny which makes for great costuming. Still not something you want them gnawing on, alright?
Again, if you have kids that can't help but chew on anything in reach, don't give them metal objects of any sort. Just plain don't sell or market to someone else's kids. Know what's in your work and what potential hazards are involved, and draw your line strongly short of risking such hazards for your own protection.
In my own work. I avoid any sort of symbolism that might be taken as child-friendly. Sorry, no pink hauberks with a Hello Kitty inlay... unless you can prove you're over 13, and want to pay alot for making me look at that much pink. A good portion of my market is strictly the 18+ crowd. No explanation is needed there.
Short version, just don't do it. If you do, use safe, lightweight materials for clothing, or "armour-like objects" not armour. In jewellry, know your materials and their contents, and the age and maturity of your customer. If you are marketing to a younger crowd, be fully aware of the standards set forth by the CPSA.