Good question. I don't know how prevalent piracy is in smaller scales, and by smaller scales, I take it you meant 1/72 and smaller. But as the others have noted, the country of origin for the product can be a red flag right from the start. I generally assume that something from Red China is a copy, until I can see information to suggest otherwise. Russia and other Eastern European producers are right behind, along with SE Asia. That's not to say that every single thing coming from an eBay seller, say, or some other vendor located in the Ukraine, for example, is a copy. But I will be suspicious.
Be careful if you consider the price of an item as a means of determining its authenticity. I have seen a trend among Red Chinese eBay sellers to list recasts at prices close to or even greater than that of the original. For example, Brickworks makes 1/20 resin figures that go with the Maschinen Krieger series of model kits. Single figures generally retail for around $30. Now, for a long time, I have seen pirated copies of those figures on eBay, and generally at low prices, seven or eight bucks, say. But starting around a year ago or so, I noticed copies of the latest releases going up on eBay, for over thirty or forty. I think the pirates think that they can fool people who would otherwise turn down a cheap item as an obvious copy, by charging the retail price.
Also, on eBay, many of the sellers are brazen enough to state plainly that the item is a recast. Though, I've noticed some that used to note this are now leaving it out. When I see an auction and the seller states that it's a recast, I report it, and cite the original maker, if I can (eg, include a URL to the maker's website/catalog).
But your question about smaller scales makes me wonder if there is an area of scale, below which it becomes too expensive to copy such figures, compared to the return.
Prost!
Brad