A new 1.7 switch feature?

We seem to have given switch a new ability in 1.7, it's possible to
switch a unversioned path:

svnadmin create repo
svn mkdir -mm file://`pwd`/repo/A
svn co file://`pwd`/repo wc
svn sw file://`pwd`/repo/A wc/X

Now I see:

svn st wc
     S wc/X

and

sqlite wc/.svn/wc.db "select * from nodes"
1|A|0||1|A|1|normal|||dir|()|infinity|||1|1289910810354827|pm||||
1||0||1||1|normal|||dir|()|infinity|||1|1289910810354827|pm||||
1|X|0||1|A|1|normal|||dir|()|infinity|||1|1289910810354827|pm||||

In 1.6 the switch fails with an error that wc/X was not versioned. It
is possible to make 1.6 do the switch:

svn mkdir -mm file://`pwd`/repo/X
svn co file://`pwd`/repo wc
svn sw file://`pwd`/repo/A wc/X
svn up -r1 wc

That results in a similar working copy to the one obtained by switching
a non-versioned node.

Is this something that we should be supporting?

Perhaps we should get rid of the externals code and use this instead?
Yes, it appears to work for files.

-- 
Philip