Should one give away ideas ?
Absolutely, ideas are like seeds, spread them far and wide. If you cannot sow them into trees, it is better that you give away. Someone might be able to grow it. Idea is just a potential, it becomes valueable only on implementation. Patenting or protecting ideas, often limits its growth.
Let public (others) see your ideas freely. You may just want to know when one of those seeds became a tree, maybe the gardner will give you some credit.
In other words, have lots of ideas, choose few to grow into trees, rest give out for free.
What about Prototypes ?
Protect prototypes like a plant nursery would protect plants. Allow selected members to view and use it. It is very important to know who and what they use your prototypes for.
This is the easier part. Everyone knows that once a product is matured, one wants as many people to see it as possible. But in the current information / innovation overload, do we have time to look at more trees ? (products). Unless we have been involved in growing it from a seed.