Definitely have seen that trick before. Also, the seller trying to assert that he collects 100% of the rent every month, every year for all the rented sites.
I only look at CURRENT rent roll and examine the tenure. Red flags are a sudden uptick in renter in the most recent few months. I like to apply a 5%
across the board discount to the annual rent roll, but I will allow the seller to disprove this by documenting actual collections bank