It's not uncommon to have third-party modules to export names,

I always explicitly specify the functions I import for other reasons, so it doesn't matter what third-party modules export.

use B qw( );          # Import nothing
[download]

use B qw( foo bar );  # but not moo
[download]

It doesn't solve the problem, but it limits the chance of it happening.

use B qw( moo );      # doh!
[download]

If you were paranoid, you could import as follows:

use B qw( );
BEGIN {
   *_moo = \&B::moo;
}
[download]

Then the imported sub will be named _moo. But I don't think it's worth the effort.