And just a note, I have no problem with you providing a challenge to MG adverse players by throwing some conventional infantry at them. My fear is that if their reaction to conventional infantry is still to avoid MG ammo, you'd escalate till they "felt the burn". IE. You are out to punish them, not challenge them. Don't be a bully.
I wouldn't have a problem with half ton of MG ammo loaded. I don't disagree that MG ammo is ridiculous. Others made the good point that commanders and quartermasters would wonder about pilots that didn't take ammo for weapons or dumped perfectly good ammo on the ground.
I don't have a problem with taking units that don't have ammo in the first place. The problem is the manipulation of the game.
Player: "Battlemasters are great! (Except for the MG's!" "I dump my MG ammo every game or never load it."
Me: Really? Why not just take a different unit? Battlemasters are designed to be capable of fighting at all ranges vs all sorts of opponents."
Player: "Yeah, but we usually face mechs and I don't want it to blow up."
So what the player has done is used info outside the game, the fact that most games are mech and maybe tank centric, to their advantage. It doesn't have anything to do with the story (if there is one), Campaign (if there is one) or anything. It's an act that is "I want to maximize my chances to win." Which in most senses is fine. There are some things that push the envelope of good sportsmanship. Lobbying for a big board say 3 x 3 mapsheets (or bigger) and then plopping down A force of entirely snipers.
"Oh I get it, you have a specialized force and on a small map, you wouldn't have the room to snipe with 4 Griffins (a bit of an exaggeration, but it makes the point)"
The player took info outside the game "We are using a big map" and used it to their advantage. Same goes for pushing for a small map and showing up with a lance of Hunchbacks.
Now I like playing with rapid fire MG's. It is actually what I think the MG's rules should be. In a campaign or storyline setting, makes perfect sense to not reload.
OK, Battletech ammo isn't very realistic. I never thought it was. Play anyway you like. I just don't think it's very sporting to just dump the ammo or ask to not load it. If you want a Battlemaster you get the good and the bad that comes with it.
As far as punishing the players. It's not an instant reaction. I'd certainly say something but if it was some sort of standard practice? Sure, time to see why you keep your MG ammo. (or whatever you want to do)