To my knowledge, they have no issue with this. The reason why they wouldn't have a problem with it is because it doesn't undermine their profit mechanism.

They take their cut out of the pool first and then pay out the winners, so however we structure our bets is of no consequence to the site owners.

By contrast, traditional betting houses give betters fixed odds that are less than fair. That means they make money in the long run, but can lose on any particular bet. Since they can lose money, they don't allow certain systematic betting behavior that opens them up to losses.