Yeah, probably the authorities will be very quick to get in touch with you for a little 'chat' about advertising for flying complete strangers for money in this way! Who knows how many 'close' friends you'll make during your spell inside.
I'm not talking about advertising through some kind of "media", don't know how you name it but only to people you know and their relatives or friends. The money you take is only to share the cost to have some fun together. In this way I use to pay 50% of the overall cost and pax. the other half. Worked for me and other people without having any kind of troubles.