Personally, all my code open source is in public domain (CC0). SO it's a free game. However taking any other code without any regard to license,or author's perm

Personally, all my code open source is in public domain (CC0). SO it's a free game. However taking any other code without any regard to license,or author's permissions, is unethical and undesirable. At the very least add a comment in the generated snipped where the code originates from. That won't suffice in all cases but it's disingenuous to profit from others' work without any credit/permission.