(FORTUNE Magazine) – Is mankind ready for another World's Fair? The people of Vancouver, British Columbia, certainly think so. Expo 86 opens there on May 2 with Prince Charles and Princess Diana on the scene, and organizers are already counting their receipts. Says Chairman Jimmy Pattison, a local businessman: ''We've sold tickets for 13 million visits. Fifty-four foreign governments are participating, and we have more than $160 million worth of support from corporations like General Motors, Coca-Cola, and IBM.'' Still, Pattison and his colleagues are trying to buck a trend. The 1982 Knoxville extravaganza earned its organizers exactly $57. Two years later, organizers in New Orleans planned on 12 million visitors, got 7.4 million, and ended up with some $35 million in unpaid bills. Both were privately organized. Expo 86 will also lose money: between $300 million and $400 million, according to Pattison's estimates. But it is sponsored by the government of British Columbia, which hopes to cover the shortfall with additional tax revenues from the eight million tourists expected in Vancouver. The province, Pattison declares, ''will break even at worst.'' Investors of a far different sort hope to do even better. Vancouver police have seized more than $500,000 in phony U.S. bills since the first of the year. And an army of out-of-town prostitutes has invaded the city. They know a good prospect when they see one.