I understand about the tears, I've sat in IT crying feeling a right wally.
I think if you gain again and you ask her before IT starts not to mention it which she ignores then you know she isn't going to change and you can make a decision about whether she is the right C for you. It may be her policy to read them out but if specifically asked on the night not to she'd be stupid to do it. You're her customer and she might lose you.
In our group normally the C will say something like 'X has a total weight loss of X, a slight gain this week of X amount so can we help with anything?' I've noticed though that she doesn't always mention the gains in number, whether this is her having been asked not to or whether she just forgets I don't know but people don't seem to get upset about it so perhaps she knows who she can mention it to or not.
Jaylou is right that we need to talk to our C's but it isn't always easy and sometimes we don't click with people we want to. All we can do is try and get our point across, if it's then ignored sometimes the only thing to do is look elsewhere but I think they'll always be parts of every group that some people hate. I have a friend who goes to a group where the C is very strict, she'll show her displeasure at gains or less than 100% attendance and effort, for a lot of people that would feel too much like school yet it's a big group. What works for one person is another's nightmare.
The main thing though is that you feel comfortable so do the best for yourself. Too often we just make do so we don't draw attention to ourselves but you're losing weight for you which is a hard thing to do so make it as easy as you can for yourself.