This is about whether you can use welcome in a "non standard (mistaken?) way" to mean the most usual meaning usually associated with it? The following casual examples will showcase what I mean:
— Thank you.
— Welcome (to mean you're welcome).
[ I arrive at some friends' place ] — You're welcome to our home! (to mean Welcome to...)
This sounds off to me. The first example must use a verb i.e. you're welcome if one is expressing gratitude here, otherwise this is about welcoming someone; the second sentence means I'm free to use the house as I please in my book, as it's not using welcome alone or we welcome you.
Considering what was intended in terms of meaning here, are those blatant mistakes or does context make it "right"; is there some kind of informal leeway with the language in that respect? Will a native speaker ever say this to mean that?