May be not.
When you join sportsbet(any site), you are making an agreement with the site. You also have some implied agreement.
Direct agreement with the site- Terms and Conditions of sportsbet
Implied agreement- Sportsbet will not scam me, they will be fair, they will send me withdraw as faster as possible etc etc and showing a cause to an accusation against you also because you know sportsbet is not like some other so called casino. So, with many other implied agreement, I would say transparency of the site is another.
If you only being accused of multi accounting but there is no proof of how you are connected to other accounts will be kind of breaking an agreement in my opinion.
Anyway, the scam thing seems to be controversial here. Looking for more explanation from sportsbet. They must be transparent.
Couple of weeks ago when a guy claimed to win 171 BTC in bitcasino, many people supported, congratulated him. But when bitcasino shared all the information with greater transparency, everyone trusted them and there was no more question.