Since is clearly not the same as as long as in the first sentence as it would imply that s/he is going. The synonym providing could be used.
"As long as you're going, I'll go too" and "As long as I've got my boots on, I might as well go out and get the firewood"
I doubt anyone would say this expecting 'as long as' to be understood "given that, because".[....]
"I'll stay as long as you need me" indeed can mean either "I'll stay during the time that you need me" or "I'll stay as/since/seeing that you need me." So weird!
This clearly doesn't mean your second suggestion - since/as/inasmuch as/seeing that. I'd add because."Golden Hawk can label its watches Swiss-made as long as at least 50 percent of the value of the movement comes from Switzerland."
No, you have done nothing of the sort.Well, looks like I've dug up here something big for you fellow native speakers to rack your brain over...
Indeed, the context is not an issue with this sentence. If you were using the ears of a native speaker, you would know that the sentence "Golden Hawk can label its watches Swiss-made as long as at least 50 percent of the value of the movement comes from Switzerland." can only have one meaning, as Thomas Tompion has already explained. The three other suggestions in your post #21 are of no relevance to the meaning of "as long as" in this sentence.Well, if one doesn't know the context which is involved in this sentence, all three suggestions seem to work just fine to my ears