I agree with you...I've read all 20 some pages of Indiana vehicle lighting code, and there'* nothing prohibiting ground effect lighting.

However,
I was stopped once at a red light and a bicycle cop rolled up and ordered me to turn my neons off because quote "Green is reserved for coroners" haha yeah right. However i have a friend with blue and he was ordered to remove the neons from his truck. I don't know if he got a ticket or not. And this was all in Richmond, Indiana