And that's another important point people miss. If I buy some tobacco and I find it has mold as soon as I get it, I may be able to get my money back or get the tins replaced, depending on whom I bought it from, etc. But no business is going to replace tobacco I left in a tin several years ago.Unless in my shoes, I couldn't see inside the tin. Transferring it sooner wouldn't have prevented to mold, but I would have been able to see it sooner.
And some tins are better than others, to be sure. Those C&D tins are cheap, flimsy things, for example. Square tins are notorious for being unreliable.
Full disclosure: I don't really care about cellaring or aging. It's a nice bonus, but it's not something I invest much effort into. I jar my tobacco for sake of freshness. Once I crack a tin, if I don't put the baccy somewhere with a good seal, it will just dry out and go bad anyway. I find I like to bounce around between blends, so I may try one blend one day, and not pick it up for several weeks afterward. Just depends on my mood. Jarring helps me accommodate that.
Everyone is welcome to jar and cellar in whatever manner they think is best. But, I don't think smoking mold is a good idea. And I don't think these mass produced tins that most commercial manufactures ship tobacco in are very good. I've read enough horror stories on this forum alone to make feel pretty convinced in those two points.