Unfortunately, we recently got some evidence of harm from the fake fur industry. I'm not sure how large it is compared to the benefits of reducing fur use, but it's no longer a myth we can completely disregard:
http://news.sky.com/story/real-animal-fur-sold-as-fake-on-british-high-street-10832370
We may need to move to alternatives that are more obviously synthetic. At least when it comes to potentially difficult to tell apart materials.
Unless regulation can actually step in and enforce labeling here... but that seems unlikely.
We've seen the same issue with dairy cheese being advertised as vegan cheese in restaurants in L.A.
To somebody in the know, it may be obvious that it's dairy by the look of it (daiya is not that convincing), but it's possible to be misled.
Even when consumers want to be ethical, deception can make that difficult since many sellers don't care. That is the danger to look-alike products.
I don't think the harm of accidents and occasional deception outweighs the benefits of competing in the market and reducing use of dairy or real fur, but it's something to be considered carefully.