I roleplay with guards sometimes too
The best my roleplay with guards is my "fail thief" alt with name "my boyfriend" who always fail steal to produce guards' dialogue line with that name. First it was created to troll guards, but then I understood that this super troll name trolls everyone who even see that character and read his name. When I blocked some guy, he requesthelped and Jovanka appeared there, and he said that his boyfriend blocked him, I was laughing so hard that couldn't respond to Jovanka, being in jail, so she thought that I'm afk and released me.
Oh and roleplay with Sha Enin was serious, too bad they replaced him with pseudo Sha Enin aka Seymour or whatever his name. Smart devs.
Also I like to roleplay with NCR guards by playing role of NCR capturer and locking them in different places, so they won't protect NCR from attackers. Also enslaving shopkeepers by locking them in brahmin pens, doctors' toilets, BoS bunkers or NCR prison.
Also I was filling Buster's tent with mercs so I could roleplay Buster's head security. Of course no one would enter tent, because there was no empty hex and Buster was pushed into corner and was staring into wall and was permabusy, but oh well.. it was for his protection.
Too bad GMs are against that roleplay and always interrupt me or even ban me. And how can I do RP here? They will never understand me. GMs ruin my RP, that's the only reason why I'm not RPer anymore.