There are two asymmetrical cases; one of them needs two pieces of information, the other three. Having to always specify both tables would syntax wise be redun

There are two asymmetrical cases; one of them needs two pieces of information, the other three. Having to always specify both tables would syntax wise be redundant, but I agree it’s worth considering it might be a good thing to improve readability, which would help especially in the case where the foreign key isn’t/cannot be given the same name as the referenced table.