Baby shower etiquette

So my mom is throwing me a baby shower... I sent her a list of my friends and addresses. Well RSVP date has come and people are emailing my mom literally asking if they can bring their friend, their little kid (rowdy 3 yr old boy), etc... Why do people do this? I know it's a baby shower, but I don't want toddlers running around pulling down decor. How do I kindly tell this friend not to bring her 3 year old? I want a stress free fun day with my girlfriends. I understand a newborn baby coming, but not a toddler! Also, if the invite says RSVP and people don't, does this mean they aren't coming? I think it's rude not to RSVP. Wow, my crazy is coming out! 😜