Asking family/friends to be vaccinated?

Jenni
We are having a sharp increase of whooping cough cases in the area I live in (Alberta, Canada). I'm asking my family and close friends to get the Tdap vaccine before they visit the baby. My sister in law, who is due in June, says I'm overreacting, because she didn't ask anyone to vaccinate at all and she is due next month. Is this really such a bad thing to ask? I'm not saying they can NEVER visit, just that if they want to come before the baby has her own vaccinations (2 months) then I'm asking they update their vaccines. Otherwise they can wait until she's two months. Is this such a big deal?