Should I poke a hole in the air mattress?

Question

So my mother brought an air mattress for my sister and her son to sleep in when they come over. They have no reason to be sleeping over here every weekend, they have their own home to sleep in and our house is not a hotel. I was thinking of discreetly poking a hole in the mattress this week. How do I do it without making it obvious? If they question me what should I say? 

Update:

They don’t have respect for where I live. They don’t deserve to be here

Answer 1

I wouldn't do that,  what if you would like to use it sometime or someday for a friend or someone you like to spend the night with you.  If it is available.  

Answer 2

Damaging a cheap air mattress isn't going to stop your sister's visits. Maybe use your words and talk to your mom rather than being a passive-aggressive creep. 

Answer 3

i wouldnt do it, they have a right to come over and visit your mother

Answer 4

Unless the home is in your name, then you have no say over who is allowed over. Grow up.

Answer 5

Show your family some respect.  Don't be a troublemaker.  IT IS NOT YOUR HOUSE..IT IS YOUR PARENT'S HOUSE. Grow up. You are very  childish and immature.  WHY DONT YOU GO SLEEP IN A HOTEL???