What about the scenario of "I can't be bothered to declare the variable and I'm the only person who's going to see this mess anyway"?
For that scenario I think it's best to work in non-strict mode, i.e. to change the "bad text" color to some "normal" color.
I'm thinking to implement some kind of toggle button for "Strict mode" on the toolbar.
It will help in situations when you work on your code in Strict mode and suddenly you need to try some code from the forum or from the code archives with undeclared variables. You'll probably be too bothered to go into the color scheme settings and change the "bad text" color to white or something normal. Now , instead of going to color scheme, you'll have to only toggle strict mode for that file and IDEal will color all "bad text" as normal text ?
Anyone need this ?