What did frighten me, though, was that the bank balance was. Whew - issue averted and my population of 90K is OK. I was almost bankrupt, so I changed tax rates and such, got things to come around nicely. So I took my sandbox city, made a copy of it, and opened it up without the Unlimited Money mod active.
So in order to unlock a bunch of buildings on one of my mega-maps, I decided to play without mods (I was not able to unlock all the buildings with the one unlock all mod, so I decided to play the game 'legit' - best decision I could've made and I parlayed all I learned into a successful city!