Yeah, one of the reason is to try recovering the money that they already lost or they both addicted and just wanted to keep playing, and when they notice that there's nothing left they start to point finger to other people making it more look like someone access the account and move the money to a gambling site, which is not hard to prove nowadays as there's already security check that may allow the investigator to look on the devices and geophysical location where the last access has been done.
They can't just blame someone and let the investigator believe that they are not the one who are in-charge on those transactions.
Things like this often happen and it would be shame because other people who don't know anything and are not involved in the betting session they are carrying out are affected by the mistakes that cause them to lose.
If I saw such gamblers directly, I would strongly emphasize that the fault lies with themselves and not with other people, that way they will realize that it is not appropriate to blame anyone for the losses they experience.
After all, they lost because of their own uncontrollable ambition and emotions, so blaming other people will only cause more complicated problems.
I sure someone who is blamed will definitely not be able to accept it because they didn't do anything but have to bear the consequences of their defeat, maybe there will be dispute.
It would be much better to have sense of responsibility for every decision they have taken, they decided to risk money in gambling so that they also have to accept the risks and consequences.