Can't 100% say they are wrong. What would happen if we hit the 10% supply cap is conversions would be blocked and ability to grow the supply of HBD would stop, meaning it could pump a lot higher. This hasn't happened yet, and won't happen as long as the price of HIVE keeps going up, but there is no guarantee.

However, even in that case, the HBD stabilizer would continue to work, and the higher the pump takes HBD, the more HIVE the stabilizer is able to buy and send back to the DAO, so this isn't all bad. It would be a speed bump in establishing HBD as stable, but still likely good for Hive stakeholders in the short term.