I'm not saying it's right it wrong, just that is what it says online. I've had siblings in the past and I never knew they needed to be separate so I only gave one receipt too. Thankfully I wasn't audited!
It says to put SIN on as well but I have spoke to my accountant about this and I don't write it on the receipts. Accountants might give different advice which is why I suggested the OP should speak to hers because if she's ever audited it will be the accountant helping her with the process (at least they should be!)
I don't give my SIN number out. If it turns out they get audited and need it, I will give it at that time.