Has C4 ever been a one hit kill to a tank? I could have sworn it was 2 to destroy. Given the length of time it takes to both make the approach, plant 2x C4, and detonate (ideally without killing yourself though I understand some planters don't care), I don't think there's anything 'instant' or 'one hit' about a C4 kill. I'm still of the mindset that only careless tankers get regularly C4'd, and there is no need for a certable defense, given you get the second seat in a MBT free. Lightnings are nimble enough that it should seldom, if ever, be an issue. That said, I wouldn't oppose a certable option, assuming you had to make a hard choice between combating C4 damage over another, more likely, damage source. That would be a far more preferable solution than just using a heavy hand to nerf C4.