So it's not entirely good enough to say "Just follow the arbitrary rules in order to demonstrate that you are a thoughtful, well-educated, intelligent person." It's always a case of pick your rules and your battles.
Similarly, perhaps online the use of American punctuation is becoming a negative signal, showing pedantic training as a "professional writer" rather than a true ability to convey ideas.
If you are looking for a technical writer, accountant, copy machine operator, security manager, etc. a rule follower is okay. These people don't ask questions, don't go against the grain and can be relied upon to simply produce output in a well structured process at a uniform consistency. In effect they are trained to produce fast food. This can be highly desirable in many cases -- but it shouldn't be lauded.
If you are looking for a novel thinker, a rule follower is the last place you want to go. You'd want them to know the rules, and be familiar with them, but not be chained to them/use them as a crutch or excuse. However, like most creative endeavors, if can be hard to get consistent, regular output. They aren't unaware of the rules, they simply ignore them. They aren't better than a person that can assemble words into sentences with the regularity of a automated assembly line, but they are definitely different.
Where it gets confusing is knowing the difference between somebody who purposely ignores the rules to achieve a desired output vs. somebody who is completely ignorant of the rules. I've personally found that people who are strict rule followers have the hardest time with this distinction.
There's something about knowing that you are breaking a rule that makes it feel more legitimate to me. You are using your license instead of your ignorance. I enjoy seeing that in what I am reading.
Edit: I wrote this in part to encourage you to relax your style and care a little less. Tell me what you think :)
So this argument seems only to hold if you a) assume that your readers are from the USA (or NA in general, no idea about Canada?) so that they value this style and b) that they don't just stumble upon your texts: They need to know where you're from.
This is necessary because it seems that a British person could easily claim that you're incompetent because you follow the exact rule we're talking about, but it doesn't apply locally for him. Okay, that's a bad example. AE and BE in writing is probably different enough so that someone speaking/writing BE will just chalk this up as another difference.
But here comes the rest of the world. We know about fall/autumn, colo[u]r and whatnot, but I'd say that it's not generally easy to say where some english text originates from, geographically/where the author lives. So if I cannot distinguish AE and BE with certainty, do I blame you or a BE person for handling this "wrong"?
Language evolves over time, and in my opinion logical punctuation has become common enough to be a credible choice. Most people these days take the "do not end sentences with a preposition" rule with a grain of salt, and I think that the MLA method of quoting is headed in a similar direction.