Why would you think it will not work? What's up with the negativity, doubts and discouragement in our culture? If you have nothing important to say, just ignore the thread. FYI, I have seen a very successful joint venture business where all of them met through sajha.com. It happens. I'm sure he/ she is not a teenage and he knows what he is getting into. There must be a reason he needs a partner, so your "common sense" advice is a waste of his time.
I wish you luck and liquor store is a better than gas station these dsys, I think. I have families in gas station business who say it is not good these days.