Tip 323 and file join

I noticed TIP #323: Do Nothing Gracefully explicitly excludes
file join. I'm okay that there is some good reason for doing

But I was wondering if the simple trick of appending "" to
the command is safe? It seems to yield the same results.

For example:
file join {*}{} ;# fails
file join {*}{} "" ;# success
file join {*}{a b c} ;# okay
file join {*}{a b c} "" ;# same as above