Conflict with PIL

I jus want to rant.....sometimes i felt my PIL jus brainless... they remove my baby car seat becoz they said the car seat occupy 1 seat coz we got 4 ppl, with car seat only can sit 3 ppl. I am so angry, few times wannna ask them to get out of the car. Always carry my baby on thier lap instead. No safety common sense at all! Told them many times it is the road traffic rules n safety but they jus too stubborn..