Thanks for all the feedback, everyone. I was inclined to snip off the tag anyway, based on observation and experience, since so rarely ever see anyone wearing it. I suppose only out of ignorance or arrogance (or both?) would anyone actually leave it on. Considering tailors remove them, I guess it was a stupid question in hindsight, but you know how it is when a question crosses your mind and you can’t stop thinking about it because you don’t know the real answer … and proper fashion etiquette can be a mysterious subject that some are embarrased to ask questions about. 
Thanks again.
Precisely that to which I was referring in my OP … it’s precisely these sorts of ostentatious jackass trends which are so gaudy and tasteless that make people really wonder what is a fashion faux pas and what isn’t. These celebrities attempt to begin a stupid trend and then people who don’t know any better think it’s the cool thing to do. Such is the reason I even question my own thinking when it comes to this kind of stuff. 
Upon viewing the posts in this thread, my opinion is:
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If you’re a high profile rapper, leave it on.
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If you’re anyone else, cut it off.
Why, a gentleman’s valet should be at the ready to take care of…
…what?
Oh, dear, terribly sorry, young sir. Maybe we should find something more practical on the bins in the discount department… 
But yes, as Zsofia points out, it’s finer, dressier shirts that use the removable stays any more.
On a related note, you should also remove the stitching keeping the pockets closed.
Re: Cuff Tags
Cut them off. As I can’t buy any suit “off-the-rack” without alterations, by the time the suit is returned, they are gone.
Re: Miscellaneous Suit Tips
Leave the outside pockets sewn shut. You really shouldn’t use these for anything. The suit will lay on your hips and look much better with those pockets empty. I do open up the top pocket, for business cards only, but even that could be kept closed.
Re: Collar Stays
Yes, they should be removed for laundering, and replaced when wearing the shirt. I use an old, small prescription bottle as the storehouse. I also have a set of gold-plated stays in varying sizes. I like these best because of their weight (who really cares about the color of a color stay?). I do tend to lose collar stays, but I also have plenty, and it’s not like you can’t use the same one all week long (as long as it fits in all your shirts).
Ha! I knew it! I have long wondered this myself, since I never wear men’s suits, but years ago I was totally outnumbered in an argument about it (and not one of my adversaries was a rapper)! I was right! I was RIIIIIIIIIIIGHT! 
Although I do not wear men’s suits, I do wear women’s coats, and although I take the tag off of the sleeve (if there is one), I leave the pockets sewn shut, partially to keep them lying flat, and partially so that I won’t be tempted to gob them up with used Kleenex all winter long.
I think that this would be a swell time to mention that the leather ‘tag’ on a Coach bag should be removed, too.
My 14 year-old, who is white, thinks he’s a Black Rapper.
He bought a BB-Jersey the other day, and left the tags on!! as he wore it.
I never saw him do this before, so it must be a new thing, as others have said.