before you start calling get_posts(%custom_code_here%) then you can use the_tags().
For reasons I do not know there’s a check
if ( ! $id && ! in_the_loop() )
return false; // in-the-loop function
in the get_the_tags() method. Seems redundant since a little further down the code it checks if $tags is empty and if so returns false. That would catch any erroneous (i.e. empty $posts) calls to the_tags one would think.
Well, it’s solved now but if anyone can benefit from this monologue, all the better. 🙂