If standing next to a friendly machinegun or someone is firing a weapon close to you that is a friendly you should not be suppressed. If anything a friendly machinegun or heavier weapon near you should lower the enemy suppression effect due to it being a morale boost.
I can understand friendly fire being suppressive if it's from a ways out and you are being shot at in a blue on blue incident, but otherwise it should have no effect or a slightly positive effect on you.
I can understand friendly fire being suppressive if it's from a ways out and you are being shot at in a blue on blue incident, but otherwise it should have no effect or a slightly positive effect on you.