Probably true. I suspect the instructions on the package also tell you to take two. But I don't know that I would call it a conspiracy. It's a marketing tactic called up-selling. It's also the reason that tooth paste companies show people putting a great whopping dollop of tooth paste on their tooth brush in the ads, when a modest amount will do the job. It's the whole philosophy behind the super-size strategy on fast food. It's the reason that the need to do something about Iraq was escalated from Sadam being a cruel tyrant who was mistreating his people to making him a member of the axis of evil who supported global terror and had weapons of mass distruction.
Pretty impressive run from Alka Seltzer to the war on terror, eh?