His aliases wouldn't be in scope there.

Thanks a lot! Here is a better explanation https://unix.stackexchange.com/questions/362546/what-is-the-... . This seems like a decent gap in my knowledge.

Is it still going to be out of scope if he e.g. runs the shell script from the shell?

Not if the alias is in .bashrc / .zshrc and they execute the shell script in the normal way. If they source the script, sure. But no one runs scripts that way, for this exact reason.