I'd rather it just remove the spaces.
Why go full tilt like that? Just implement spaces and see if it drastically drops scamming. Then go to the annoying stuff if necessary.
Making it so multiple spaces get automatically reduced to one space is more than enough to stop these kinds of scammers because the scam relies on the chat box's ability to allow those many spaces to go through. Honestly, there's no reason for anyone to use more than one space in any kind of conversation, so why not just have the chat box not allow more than one space?
Removing multiple spaces reduces the range of chat window widths that can be fooled by any particular padding but does not eliminate it. Phishing scammers don't expect their tactics to work all of the time, or even most of the time. They would just continue preying on the most vulnerable by targeting chat window sizes that are close to the default, like this:
Keep in mind that the people who fall for this scheme are somehow completely oblivious to the lines of text that currently look like "skjdlkasjldkajs : ..."; the text in this screenshot, which doesn't contain any multi-space sequences, really doesn't look all that different.
I've put much more thought into this problem than you realize. Of course I'm open to suggestions, but all of the ones proposed so far (I counted two) have been either insufficient or unworkable.
:3
D:
I use colons all the time
Funny story: the first time I mentioned this (when the scams were still "new") I said something like, "that way people can still have their emotes."
So basically ;_; becomes =_= and Avatar: The Last Airbender turns into Avatar= The Last Airbender.
Just remove the chat feature altogether then, because just lazily replacing : and ; with = goes beyond simple scam prevention and into the realm of obfuscating legitimate communication.
Also=
Just because it happens doesn't mean it's right nor that users want it.
It's strange that someone who made such a big deal of "the needs or comfort of those around" would be so willing sacrifice so many real victims over such a trifling inconvenience, or to equate that inconvenience with the inability to communicate altogether.
In any case, it seems that the plan was not accurately communicated. The substitution happens only if the character has spaces on both sides--so none of the examples anyone has offered would actually be affected.