Even though some myths are most likely fake, there is still a possibility of them being in the game. It is for this reason that we have the Unlikely existance label.
well technically anything could be set to "unlikely". IF somebody really thinks that its possible for a working time machine that transports you into GTA V on PC on max settings, and there would be "a chance" of it happening, no wonder somebody will think piggsy is in the game. He isn't, ok? and, if he wwas, tell me where to find him in th game files