Am I wrong ??

So I get married this year and my engagement party is next month and the dress code is business formal, no jeans or sneakers. The party is at a country club and is themed and my SIL has an issue because her son (15) can’t wear sneakers. She called me and said ‘so you would rather your nephew not be there since he can’t wear sneakers’. I didn’t really engage in it because the dress code is what it is there’s no discussion on my end to be had. At this point I don’t want her in my bridal party because I feel like she will complain about the attire I have picked. My wedding dress code is black tie formal so that will really be a thing 🙄