Put stuff like names, usgn ID etc. in the mapfile? Forget it! Can be replaced/removed very easily!
Encryption? Forget it! It must be decrypted by the game anyway otherwise the game wouldn't be able to load the maps! This means that the encryption algorithm and the keys must be in the map file or game which also means: No real protection at all.
Compile into another format? Forget it! It's in the RAM after loading anyway! You can grab the map data right from them memory.
"Wait! This all sounds complicated! Most noobs will not be able to break those protections!"? You are right but I know the CS2D community and there will probably be some idiots that invest some time to write tools that everyone can use to achieve the things above. I'm not going to implement worthless map protection attempts.
Also: If someone wants to copy a map really hard he can do it by just viewing it and copying it tile by tile! CS2D maps are super primitive so this works quite well and there is no protection that would ever be able to stop you from doing that.