It's not the ice cream, it's the cone. they're ensuring he'll be back for another chat oh so very soon by taking advantage of his frazzled mental state. The cone is a wheat byproduct, and he'll eat it without ever even noticing.
I have this weird headcanon that I'm sure everyone's going to reject, but I thought I should tell you. ; v ; So, here goes: Carlos is actually an undercover member of the Sheriff's Secret Police. He was chosen because they, and others that are watching Cecil, know he's the man's type. He was hidden for whatever reason for a very long time, but was forced to come out and into the open to publicly get closer to Cecil. This makes him interesting, but non-threatening. The one who runs the re-education process Cecil has to get time and again is actually Carlos: he just never remembers because he's supposed to not remember. And each time Cecil is devastated, and each time after he forgets that devastation. I really like hurting my loved ones, and I’m so sorry Cecil, baby, but you’re not an exception. ; 3 ; I also enjoy the possible torment Carlos might be going through because he’s falling for someone he was supposed to get close to, but not get wholly involved with. So, uh. There. ~; 3 ;~
WHAT. THERE'S NOTHING THERE. WHAT ARE YOU TALKING ABOUT.