It certainly does pose an issue from that perspective but I’m not sure any more than websites in general. It’s not actually that hard to rip off a website’s design and so it’s quite common to see phishing scams of that nature. In some sense it’s less likely to happen with people impersonating a Lemmy instance simply because actually setting up and running one is more work than impersonating just a regular website.

Yes, someone could create an instance called “officiallemmyinstancedotcom” and pretend to be the one single official lemmy to try to trap people searching for Lemmy not entirely knowing what it is, but I don’t think the fact that people already think places like lemmy.ml or lemmy.world are synonymous with Lemmy is a prerequisite for someone doing that. If anything, people who mistakenly think one of those two is the only “real” Lemmy are probably less likely to be taken in by a malicious one.

Still…

Providing clearer on site messaging to help avoid this sort of confusion sounds like something a good UX designer could perhaps assist the Lemmy FOSS project with?