"Imitation is the best form of flattery". Nowhere else is this phrase more relevant than in our field of patent practice. Clients are often worried about third parties copying their inventions. However, I would be more concerned if the invention was not being copied. Of course, that's provided the patent application is in place.
Consider the investor. Copying is a clear indication that the invention has commercial value. It stands to reason that an investor would be more interested in a product that was being actively copied rather than a product that has alleged commercial value. After all, if a patent is granted and can be used to stop the copying, the resultant vacuum could be very valuable to the investor.
The idea is not to think about patent enforcement before the patent is actually granted. Enforcement can be incredibly expensive and should always be the last option. Rather just continue with the patent application process and ensure that you get patents in place that are effective. This needs to be done in close collaboration with your patent attorney to ensure that the invention is as fully described as possible. In particular, you need to keep your patent attorney apprised of all developments. You have a 12 month window from the date of the earliest application, usually a provisional application, in which to ensure that the product is commercial-ready. That is a far better use of your time than worrying about who might be copying your invention.
It is unlawful to make any form of threat until you actually have a patent. So, there is not much that can be done until then, anyway. Also, you don't want to be placing your potential opponent or even licensee in a position in which they can disrupt your patent application during the vulnerable pending stages.
Of course, if you become aware of copying during the pendency of your patent application, you can use that as leverage in negotiations with potential licensees. Particularly in the United States, there can be significant damages for wilful infringement. That could be of particular interest to potential licensees.