The keg Kai had and pretty much any one that looks like that, is pretty likely to be an out of service keg. The oval shaped kegs dont work so well with modern kegging plants, are harder to store, stack and pick up with forklift attachments. They were phased out a fair while ago. The big 18 gallon kegs were phased out due to OHS concerns with delivery drivers having to lug them around. Or it might be a cask rather than a keg, if it has a hole in the side, thats what it is.
You can pick those sorts of kegs up legally without too much trouble, not that they are all that cheap compared to a brand new aluminium pot. However, that chances of you finding a "current" style sanke keg that is both legal and that costs you under $100.00 is pretty damn slim. If its got a currently trading breweries name on it, then its almost certainly NOT leagal. Those things cost around $120.00 to replace and thats when you buy them 20000 at a time. If yours cost $50 then somebody somewhere got ripped off.
I know from a Fosters/CUB perspective at least, that if you dont have a letter stating that you are allowed to have the keg (it'll have the keg number written in the letter) then you aren't. Doesn't matter if you bought it off some guy who said it was leagal, pulled it out of the river or found it out in a paddock somewhere. No letter, it still belongs to the brewery. If you found it at a scrap metal dealers, then he's not supposed to have it either. When fosters scraps its damaged kegs (makes me cry inside everytime) they send them to a scrap yard on condition that they are actually scrapped and not re-sold in any recognisable form. That way they know that if you have one... then you shouldn't
Now dont get me wrong, I'm not going all preachy on the having a sly keg as your kettle thing. Just dont kid yourself that its all nice and legit. It might be.... but it probably isn't.
