Swashbuckling and Armor Encumbrance

The swashbuckling proficiency requires freedom of movement and leather armor or less. This weekend, one of my players asked whether the reduced encumbrance of magical armor enabled them to be used in conjunction with the proficiency; for example, chain +2 (which would have an encumbrance equal to mundane leather). On the one hand, I like this as a nod to the elfin chain of older games; on the other, it makes a Fighter with the proficiency and sufficiently enchanted chain quite powerful- the equal to a fighter in plate and shield.
Still, it seems like a fair trade (fairly strong magic and a proficiency slot used). Thoughts?

Charlatan - I certainly wouldn’t fault you for ruling that way. That said,the official rule is that swashbuckling only works with leather armor or less. Just as a thief can’t wear chainmail +2 and use their thief skills, a character can’t wear chainmail +2 and use their swashbuckling skills.