What you're suggesting was already doable with the pre-nerf Screamer, so imo it's not really the matter of usefulness of a mine with nothing but plain EMP properties, but rather its current damage output. When Screamer had 30k-ish damage, its main use wasn't deshielding fighters in one go, but either deshielding bigger ships (esp. transports) a lot faster than guns could, or in case of snub pvp, "disabling" snubs in dogfights by dropping a screamer on them when their shields were already down, which could effectively dry their core and make em sittin' ducks for a few seconds before they could actually start shooting again, which is pretty much what you're suggesting. Basically, you could just hit an EMP bomber with a screamer and then joust it heads-on without having to worry about getting snac'ed cause the bomber's core would've been sitting at 20% or so.

Fighting people who knew how to use a screamer for anything other than insta-deshield in duels was sure annoying before the stats change, regardless of what class of snubs were in the fight. The reason that tactic, along with other uses of screamer outside fighter 1v1 don't seem that reliable anymore is mainly due to the current stats. With 14k emp damage per direct hit (which means no more than 10k probable damage if trapped, which is not that much more than a direct nuke) the slightly higher shield damage and slightly better tracking doesn't really seem like a reasonable trade-off for doing practically no hull damage at all, so even an EMP bomber would be better off just going with nukes and gun+nuking the shields and the hull down rather than going with screamer and trying to mine the shields and gun/snac the hulls.

tl;dr - No need for any fancy codes. The balance team just need to redo its stats so it can be a reliable alternative to nuke across the board, rather than the "just for LFs, those fighters who go full-hullbuster, or people who don't know how to use nukes and keep blowing themselves up" sort of minedropper it's currently turned into.

P.S: That's kinda ironic though, thinking about it... Seems like the high shield damage on screamer was considered a problem when used against fighters, even though the high damage was intended for other purposes, so by nerfing the damage to half or so, every other use of that mine was effed while it still remains just as useful for insta-deshielding snubs.