I've spent quite a few happy minutes reading Venmo's, (wide-ranging, as might be expected), T&C at
https://venmo.com/legal/us-user-agreement/ and it seems to me that unless there has been an Unauthorized or Other Error, (#D.11.), the
user can't reverse a transaction, unlike with Paypal.
Otoh, Venmo can reverse a transaction, (#B.1.f.), if they deem it to be high risk; which, presumably, includes the possibility of fraud being involved.
For these reasons, at this time, I don't see that the Venmo rules are the same as the Paypal rules, and that just because PP is barred here, Venmo should be barred, too.
I'm willing to listen to sound arguments that I am wrong, but if they are based only on the potential fraud aspect, you have to remember that even money in traders' poker sites' accounts can be found to be there through different fraudulent means, and, as any reasonable person should realise, no transfers with internet strangers by any method are entirely risk free.
I'm very happy to include a specific warning about Venmo in the OP, but, again, I really don't want to reduce transfer methods for the majority of our honest users to move money into or out of their poker accounts.