Why is '+' a delimiter in $OBDA_SEARCH_PATH?

Bioperl-l,
The character '+' is being used a delimiter in this variable instead of the
standard Unix ';'. If I'm not mistaken one can use '+' in a directory or
file name, whereas ';' seems not to be allowed. In fact, isn't "lost+found"
a system directory in some Unixes? Anyway, I will change this unless someone
can convince me not to.
Brian O.