Think person A has a great software business idea. He also knows software programming and converts his idea to a mobile application. Then he needs to raise some money to launch the application, do advertisement, hiring staffs and buying stuffs. Then he searches through the internet and finds some venture capitals, angel investors, etc. and sending a pitch and demo from his application to encourage them making a deal and investment on his idea/application/business.
But person B who is one of these investors who received this email says "Why should I invest a lot of money and just get 10-20% equity? I can call Bob who is a computer software engineer and ask him to write a similar application for me, or even better than that! So I will have 100% of this company not only 10%!".
Is it possible to prevent such a thing to happen?
EDIT: In respect to Joe's answer I like to add something that I couldn't write in the comments. I saw many of the "Shark tank" series (that I don't know if they are really investors or just showman?). When they do want to say what do they can do behind/after their money offer, they say "I will add some value to the product", "I must do a lot of work for this business that you don't know/understand", "It takes a lot of my time and drains a lot of my energy", "It is a good fit for me and I know what to do", etc.
It seems they want to say they are not only a paycheck to the business and they do not just sit and see what do the inventor will do after getting the paycheck.
My confusion is, do they want to give some money to a person/team like a loan and get back more money as their profit of investment, or they would like to engage into the business? If they do like to engage, why they don't do all the jobs by their teams and earn more money?