Jumping into a cage with tigers

Well, I just need your advice girls. You see, there’s going to be a children’s Christmas show in January (Orthodox) and I really really want to take Alex to see Santa Claus and watch all the dancing and everything, because he’s two and a half now, but the things that’s holding me back is that his grandmother (the other side) is going to be there, I’m pretty sure, because his youngest auntie is seven or eight I think.
She’s only seen Alex once for a few minutes when he was one and a half, and she acted like a hysterical idiot, jumping up and down like it was the happiest and best thing on earth, even though she’s had plenty of chance to see him, and she hasn’t. She’s obssessed with her social status, I would personally call her a socipath, so if I take Alex there, she will start her little social network of rumours and lies again, and probably come up to me and make out what an awesome grandmother she is, and start being hysterical again trying to show people how good she is, and I’m sure Alex will get pretty freaked, because he doesn’t know who the hell she is. She has many people on her side believing absolute lies about me, I’m pretty sure, and I’m also really sick of people looking at me and talking behind my back — I really want to be part of my community, but I’m not, because there’s too many retards, and everyone wants to be on the good side of the other family anyway, because they own the local Russian shop, and everyone buys their stuff from them (other than me, of course, even if I COULD go there I wouldn’t because I don’t believe I should be forced to pay for any kid’s stuff from there, and anyway, it used to be all free for me before anyway).
I just don’t know how to act if she starts coming up to me and making a fool out of me, especially with all the support on her side; I don’t even know if I should take him there at all! I just want to show him his culture, but I don’t want to have a bad outing where we both come home in tears!
Any advice???