if you use the implode()-function on an array with only one element in it, the glue string is appended to the name of the only element, anyway. i could not think of any situation where this could be helpful since the glue string is not appended to the last element of a more-that-one-element-array, either.
i, for example, use it to build a mysql-query where the glue string is "or (row-name)="; of course, mysql reports an error if it encounters something like "...=" with nothing behind the "=".
sure, one can easily work around this with an if-construct, but i think it would make more sense if, in the case described, the glue string were not appeneded to the result.