Always a pleasure to see you, Hoosier!
I'm not sure of the doomsday thinking about flavors. They will never be restricted, since the food industry would be strongly affected. I personally have not experienced any change in my flavorings just sitting in boxes in my office for years now. Evaporation would be the main issue. Some notes are more volatile than others, but if the bottle is closed, that is a moot point. If a vendor says you should store in the fridge, like the naturals, so be it. I only have one of those (LA Nat Creamy Caramel), and I have not done that, and it has not changed at all in about 9 months.
Sadly, I do not really like about 95% of the flavors I have bought. Maybe I need to cut back from my default 10%. That would probably help.
And other than tobaccos, which improve with age, any other flavored juice I make is best fresh, and over time it just fades to something I would rather not vape. So for nic conservation and just general better vaping, I make enough for a few weeks, tops, vape that up, then make more fresh as I go. Its fun to get a bunch of flavors and make 3 or 6 mL samples to try...and most of them end up getting dumped because I don't like them, and I need the bottle. DIY can be like overeating at an all-you-can eat buffet, times 100.
That said, I cannot see any harm in freezing flavored juices. If they separate, and I doubt they will as I think about it, just shake them up when they get to room temperature. It's just not something I have done as yet. Might be good for those buying commercial juices, however, if they do not want to fall down this DIY rabbit hole.