If a password is not required, it  is not checked. This is a general rule
for all keywords and prefixes, if they are not required, they will not be
checked and you will get no complaint; this saves time and a lot of code,
and  makes it  possible to  write execs  that always  send such  keywords
without having to worry if they are really necessary. For the password it
is even  more complicated, as  you can specify  a password for  the whole
job; what  then if  there are  commands in the  job for  which it  is not
required, but where  it does not match the password  that would then have
been expected?
 
  Eric