Can anyone copy a program from an MCU or duplicate an MCU?

I'm still a total newb--just got my temp sensor to work--but this question suddenly nagged me.

There are lock fuses in microcontrollers that once set prevent reading the memory of the controller. If the fuses aren't set, you can read the program off, but it will not be in C, it will be a binary file that could be transferred as is to another microcontroller, or disassembled into an assembly program (albeit not necessarily an easy to follow assembly program).

Thanks!

I appreciate open source, but also want to protect the product of my time and effort.