I wouldn't name names unless you must. It's ok to vaguely say that some people are getting preferential treatment and there are double standards, but saying direct things like, "Kathy gets to check her phone all the time and I can't," is throwing Kathy under the bus and it hurts your credibility, because Kathy is just doing what her supervisor allows. Now you're dragging her into it when it's about your supervisor and you. So instead, say something like, "two members of my team have been allowed to check/use their phones during meetings for the purposes of _____. I am confused as to why some members are able to access their phones and some aren't. I don't know if they have been granted special permission or if there is some misunderstanding, but I would like to be enlightened about this issue because the rules are not clear to me." That's the professional way of doing things. And of course, if they ask for names, then give the names, but don't offer if they don't ask.