Its part of AS abilities. Thats like saying some grand summoner isn't allowed to summon during his match...
also here is some info on the base tier mugann who could probably end Lelouch anyway
If he summons them entirely under his own power, then yeah, he would get them. He wouldn't start with any, but he'd be able to summon them mid-match.
also 'small bombs' man
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another place and time, without a great divide, and we could be flying deadly high