Are you for hands, or for bodies? Or faces? I don’t want to dry my hands on somebody’s face towel. Or the one they scrub their body with :X
In my opinion it should be clearly identified which towel is for guests. This would help avoid the awkward feeling of being in someone’s bathroom and not knowing where you’re supposed to dry your hands. I’m not the only one who feels this way, either. I have asked several friends and they have confided that this is a source of confusion and shame.
In my apartment, the “hands” towel is clearly marked as such. There is a sign above it that says “DRY YOUR HANDS WITH THIS ONE!” and it has an arrow pointing to the towel. Not only does this keep my guests from feeling shame, but it ensures they will not dry their peepee hands on the towel I use to wash my face. This is very important to me.