You are questioning the logical validity of the statements. Logical arguments (even if they have one premise and one conclusion) should be precisely worded or their validity can easily be questioned.
Take your first example, about Joe robbing a bank. The explicit meaning is that Joe did something because you did something. This is not a logical argument with a premise and conclusion at all. (It's the same form as "I used cream because you used all of the milk." There is no premise-conclusion formulation.)
If you want to infer a missing "I know that" or (equivalently) "I conclude that" to the front of the statement, it becomes a logical argument. This doesn't mean its a valid argument, though. If it's not a valid argument, then it's known as a logical fallacy.
Interestingly, logical fallacies can be categorized based on interpretation of language and how it's used. The site Logical Fallicies has a lot of information on this, and it's worth reading.
Your example of Joe robbing the bank might be considered a logical fallacy of equivocation. (I'm not a logician, so there might be a better category for this.) Equating "running away with" to "stealing" assumes there is no other explanation for Joe to be running away with the money.
Making business decisions depend on good reasoning, based on sound (valid) arguments, but decisions are sometimes based on business intuition (a combination of risk taking and experience). You second example might be inferred be identical to:
"If you have seen AT&T's recent advertising campaign, then you know that someone (at At&T) is obviously worried."
Even though this, by itself, is a logical fallacy (there might be some other explanation for the campaign), it wouldn't necessarily be a meaningless statement. There may be enough context that a logically valid argument could be made. Hearing it at a business meeting, a manager may choose to react a certain way based on this information coupled with his own knowledge of the situation at AT&T.
Does it matter, and should you just ignore it? It's good to understand that in some circumstances, knowing how to spot a logical fallacy can be important. In legal matters, precise language is always important, and a logical fallacy can be the basis for a case being dropped "due to a technicality".
The answer to the question in your title is that it depends on the circumstances. But inferring meaning runs the risk that is is inferred incorrectly. If you're just reading an advertisement, then is doesn't matter. If you're reading your own bill of indictment, you need to understand words and the concept of logical fallacy.