I expect alot of crazy people would start using alts in this freeroll or some people could probably not care about this because this is free and they just start going all in every single round.
It is not a secret anymore when it comes to a poker freeroll with a nice prizepool then some people will try to abuse it by creating alts in order to get a better winning chance. I hope sportsbet is able to minimize this kind of abuse, so all registrants are real player with single account only so the freeroll will be fun. I have experienced many times in freeroll but most players are sitting out which was not fun at all.
Alts are actually a known cheating method and as long as admin could modify their system to restrict them, you can't stop all of them at all. However going all in all the time and playing like crazy because you are spending zero money is not really that big of a deal, let them do it as much as they want to, eventually you will have a good hand and you will end up winning.
Also, if they are actually playing that recklessly that means they probably do not have a good hand most of the time, which means even with some semi-decent hand you might get in and take all of their money, you could do the risk and reward ratio of the hand for yourself and if it gets too much you can always stop and not raise or call, but I like those people since I could take all their money with just 8's or something.