Sip and see, gifts expected??

Hello, this is my second baby and we are having a sip and see so that we don't have visitors coming and going for 2 weeks like the first time.

We don't want gifts because we already have what we need from baby number one.

I put on the invitations "please join us for snacks and drinks"

But my MIL thinks we are expecting gifts and that is why she didn't want us to have a shower. (Which I didn't want anyway, but she was rude to my mother when my mom threw a shower with 6 people)

But I feel if we didn't write that we are registered anywhere, and that i said snacks and drinks, that people would know no gifts.

What would be your thoughts on gifts if you received this invite? Should I make an insert that says no gifts (but that seems tacky because it would be a separate sheet since the invites have already been made)?