As a newer boat and lakehouse owner, I might not be up to speed on the gas etiquette issue but this is how I handle it. Typically, we have friends and family up for the weekend and i'll assume i'm paying but accept if they offer. If they don't offer, they might not be invited back especially if they see me forking out $100.00 for gas.

For instance,this weekend one of my best friends and his family drove in from Mobile, AL for a 5-day weekend at the lake. They insisted on paying for the first 40 gallons of gas and the groceries for the weekend. Great minds think a like.