If the crew had referred to the checklist they may have read some of the points made in the above post. My information is that the crew did not use the checklist in reference to the fuel leak problem. The Captain opened the crossfeed line - or should I say - crossfeed in-line (airbus speak) without reference to any checklist.
Furthermore, any professional crew when confronted with an abnormal situation carries out the checklist and performs each item on the list at that time. You don't just assume the fuel is OK because you recently did a check. It takes just a few seconds and some simple math to do a check.
Captain Piche's poor CRM knowledge or acceptance was a main contributing factor. It will be interesting to see if this is pointed out in the official accident report.
A310Guy