The methods to create your queries are more convenience functions and to give you a standard interface so that changes in syntax per DB Brand can be normalized and make your app more portable, if you wanted to say, switch from MySQL to Oracle.

However, since no DB is going to let you get away with amigious column names, such as what you described, the onnus is on the developer to pass the table name with the column name when getting into situations where the field could be ambigious, which with the ZF is going to be through the fetch* style, and not find. Find is only for single table look ups by primary key... in other words not for joined tables and other complex queries.