There are dedicated aquarists on the case. NoClownsInACube have been having serious dialogue with senior management at Petsmart of their innacurate point of sale information and Petsmart are being very receptive.
http://www.noclownsinacube.net/petsmart.html
Currently, people are working on providing evidence to Petsmart that the information they give out on maximum sizes and tank size requirements need serious upgrading. This is being done by accumulating expert data and photographic evidence.
It does seem that branches are run "By the book"......but the book is wrong

Somewhere along the line Petsmart were given some very innacurate information and that is being perpetuated. Hopefully soon there will be changes and a major chain like this changing its ways may affect the whole industry.
Martin.