It will only affect you if you aren't using cover and blobbing. So basically never unless you aren't playing well.
Glad to hear you're so good at this game you never have fights against 2 or more grenadiers (or JLI or Obers or Stormtroopers) while not being in green cover.
Blobbing makes no difference against this, except from the axis side where you will start getting aoe suppression as you gather up more and more grens. Two grens to suppress one squad, but three grens can already handle two squads.