When a landlord insists that you pay in cash, it is not for you to query how they record the transaction, but to insist that the amount you have paid is recorded, even if you must present your own money rent receipt book.
There are many circumstances where a landlord will prefer to be paid in cash, and this may apply equally to individuals or families renting, who choose to pay in cash. The landlord can easily custom print money rent receipt books, and this will clarify the amount of the payment, the date it is made and that it has been received.
Is the Process Legal?
There is nothing against the law for either the landlord or the renter to insist paying in cash. Where one or the other does not manage a bank account, it may be the only process available. Should the landlord require the payment to be made in cash, they would probably have insisted upon this before signing a rental agreement.
It is not for the renter to worry about whether the landlord declares the process that is acceptable to the IRS, but you might choose to question whether the landlord is carrying out all their legal requirements for insurance and safety certificates.
The Proof Is in The Receipt Book
Where the renter receives a written receipt confirming the amount paid and to who and why, and the renter is able to keep their copy of the transaction, they will always be able to provide proof that they have paid the rent and the specific dates when that transaction was completed.
The agreement provided by the landlord will specify many items and if they insist the rent is paid in cash, money rent receipt books, that are customized and preprinted, perform the task perfectly.
Just because the landlord insists on the rent being paid by cash, this does not automatically presume that they are not recording the rent and the payments officially. Although it may be strange in modern times to make a cash payment for the regular rent, there may be circumstances where the landlord does not necessarily trust the renter to pay directly from their bank account or by check.