Legal recourse after VC disclosure without NDA?

I have never seen an investor sign an NDA. Investors, like many business people, realize that an idea's "time has come" and that, in a world where innovation is coming from every corner, you are most likely not the only one thinking about the same thing. Further, investors will not want to box themselves into an NDA with you if it could cause problems with them investigating similar technology with someone else. Finally, even if there was an NDA in place and you had recourse, would you have the legal wherewithal to actually do anything about it, if they did commercialize your idea without you? Your best option is filing some sort of patent application before investor meetings. You do not need to have a finished app to file a patent application, you just need an enabled specification on how to build the app and practice the invention (this is assuming that you have a new and novel invention). Unlike an NDA, if your patent application eventually turns into a granted patent, it is a piece of property that has tangible value that can be bought, sold, licensed, etc.