My wedding is this Saturday and my SO's sister is a bridesmaid. In the past week she has:
Stolen from us, so I ratted her out
LIED about me calling her names  
Said she will not be in or attend the wedding (her mom is making her)
And then ran away and said it was because of me.  

I want tk kick her ass....out of the wedding but SO said no. She has not been punished at all by her parents. I feel so angry, hurt and disrespected by this smurf. So should I comfront her, kick her out of the wedding or other? I know I sound petty but she is ruining this whole thing!

She sounds like unneeded drama I'd kick her out.

kick her ass out, confront her, and then tell your SO how disrespected you feel! if he wants to marry you he needs to respect you and your feelings

Quoting Mrs. Weasley [tech probz]:" My wedding is this Saturday and my SO's sister is a bridesmaid. In the past week she has: Stolen from ... [snip!] ... So should I comfront her, kick her out of the wedding or other? I know I sound petty but she is ruining this whole thing!"

how old is she?

Quoting Mrs. Weasley [tech probz]:" My wedding is this Saturday and my SO's sister is a bridesmaid. In the past week she has: Stolen from ... [snip!] ... So should I comfront her, kick her out of the wedding or other? I know I sound petty but she is ruining this whole thing!"

I'd confront her. But if it is going to completely ruin your special day, then kick her ass out.
You will be the "bigger person" and she will make her self look like a fool if she acts up, especially after you give her this chance.

How old is she? she sounds really immature. I would TRY talking to her. but if she still didnt straighten up i would still let her go, but i wouldnt let her be a brides maid. its your day, and it would really suck if she ruined it for you. Congrats by the way  

She's 18 btw. And SO said I cannot kick her out. UGH.

You have confronted her and she made some serious drama.... I'd just kick her out (after talking to your SO about it).

<blockquote><b>Quoting Mrs. Weasley [tech probz]:</b>" She's 18 btw. And SO said I cannot kick her out. UGH."</blockquote>




So old enough to know better. I'd have a firm talk about expectations at the wedding.

I am going to tell Chris' mom how I feel amd that if she wants to be in it I want a handwritten letter of apology

That's dumb. You don't want her in the wedding.... she said she doesn't want to be in the wedding.... so what's the point?

Maybe all three of you (you, her, SO) should sit down and have a chat about it.

<blockquote><b>Quoting Zbornak:</b>" That's dumb. You don't want her in the wedding.... she said she doesn't want to be in the wedding.... ... [snip!] ... to be in the wedding.... so what's the point? Maybe all three of you (you, her, SO) should sit down and have a chat about it."</blockquote>




I can't because she cries that I'm stealing her brother  

I would talk to her parents about her possibly not being in the wedding because she is not showing that you can rely on her to do her part. I say her parents because you two have been bumping heads and she has conveyed that she does not want to stand for you. Kind of turn it around on them and frame it as you are asking their advice on the issue.

I would just let her drop out she clearly does't even want to do it so cut your losses.

I would tell her and your SO flat out no. You do not have to let her be a part of it and for him to force you is really unfair.