My cursory knowledge of Interac E-Transfer is that they are irreversible by the sender once the recipient has accepted the deposit.
Relevant snippet for the sender of the $50:
I need to cancel a transfer, but the recipient has already accepted the deposit. How do I reverse an Interac E-Transfer transaction?
Unfortunately, once a deposit has been made there is no way to reverse the transaction. You’ll have to make arrangements directly with the recipient. You should only send money transfers to parties you know and trust. For most Interac e-Transfer uses (sending money to family and friends, repaying IOUs, sending money as gifts, etc.), you will know the recipient well. For uses where you may not know the recipient (e.g., online auction purchases), take the same precautions you would take when making cash purchases. For online auctions and purchases, be sure to read and follow any steps recommended by the operators of these websites to safely transact.
Pay attention to "recipient has already accepted the deposit".
If you have not accepted, then reject the deposit. If you choose to send fresh money instead of reject the initial money then the other person may be eligible to accept your money and cancel their initial transfer.
Never forget that a sense of urgency is a scammer's first line of attack.
If the sender reached out to you moments after initiating the transfer then consider that as a red flag; they want to reach you before you even realize you have a pending deposit.
It would take an average person hours or days before realizing they sent to the wrong address. A person cognizant enough to email you moments after an "accidental" transfer would have been cognizant enough to not send it to the wrong address in the first place.
If the sender also supplied a different Interac address than the one which initially sent you the money then that is a definite scam attempt.
If you've accepted their deposit then you may choose to send it back as long as you're sending precisely $50 to the same exact address. At worst, you miss out on keeping a scammer's fifty dollars. At best, you return an honest mistake.
One "angle" of this scam is that the initial transfer is legitimate/honest to build up trust in an effort to set you up for a larger scam. Fifty dollars is trivial and would establish you as a valid patsy. The next unexpected transfer could be for a thousand dollars via a reversible method.
Scammers are consistently crafting their deceitful methods so potentially honest mistakes like the one they're portraying sometimes suffer.
Per Interac E-Transfer's website:
Unexpected Interac e-Transfer notification?
If you receive an Interac e-Transfer text or email you weren’t expecting, confirm with the sender via another channel. If the email or text comes from someone you don’t know, or you suspect it to be fraudulent, don’t respond or click any links. Forward the email right away to phishing@interac.ca.
