what happens if you record a type I cassette on type II setting, and vice versa?

From Wikipedia ...

Notches on top of the cassette shell indicate the type of tape within. Type I cassettes only have write-protect notches, Type II have an additional pair next to the write protection ones, and Type IV (metal) have a third set in the middle of the cassette shell. These allow cassette decks to automatically detect the tape type and select the proper bias and equalization.

The higher frequencies may be a bit off, but cassettes were just good enough sounding as things go. I found I could interchange types I & II.  You could not do that with type IV.  

Rich

Non-linear higher frequency response, distortion, tonal imbalance … how much and how discernible probably depends … play with it and see WRT your equipment and ears.

Who can say listen and compare.

After delving into the deepest recesses of my memory, I remember the differences being almost entirely that of EQ and Tape Hiss. And oh yeah...  Go back to the proper settings if acrid smoke begins to waft.............

thanks for the replies guys!

I am in a band, and I have this really great cassette deck for whenever when play, and we love to hit record on a good tape (Fuji and tdk are my preferences) and let it roll all night! 

and last night i almost forgot to turn off the CrO2 / type II setting, and I was just wondering what would happen IF i
"record a type I cassette on type II setting, and vice versa".