I do most of the time. Did steaks today and it's the first time I did not use foil. My grill is about 2 years old and I have always used foil but at higher temps it can melt. Doing slow & low foil is fine and makes clean up easy.
I agree with MikeInFla, i use foil for easy clean up.
make sure you wrap it tight around the edges and be sure to crease it in the drip channels so it drains the grease out.
Used mine without foil for a couple tri tips cause I thought I might use the sear option but it was not needed so now I have more cleaning to do.