The Word "As"

This is something that has really been bothering me lately. Everywhere I turn, there it is...the word "as." I was under the impression that this word conveys a sense of concurrence (yes, I do know that this word has its own issue, too, but let's not go there) or simultaneous-ness (if that's a word), but people use it in substitution of the word "since" or the word "because." I can't quote any real references I've heard lately because I don't know who reads this thing (no one), so I'll try and make some up that illustrate my point.

"Remove all items in refridgerator promptly as it will be cleaned Sunday at 2:00 PM."

I don't understand that. Do they want you to come and remove your things on Sunday while they're cleaning it? That's what it reads like to me.