I prefer $100 Bills and I check each bill with a counterfeit pen.I don't handle work orders.

I would even go so far as not to accept money orders or cashier's checks, as it is relatively easy to make counterfeit ones.Cash is king, especially with move-in fees.Paying for an entire year's worth of rent up front is indeed a red flag. 

Do you guys ever collect cash, I don't like the idea but I will make sure to get a receipt signed and dated. ...You are the one RECEIVING the cash, so you GIVE a receipt to the tenant showing proof of payment; your receipt ledger / register will be the place where you document for your records that you received $XX from tenant YY for month ZZ rent, and the date.Yes, I will collect cash but prefer not to; no need for me to be armed in the areas where my rentals are located.If you have untrustworthy tenants there, you might want to bring along a special pen that is used to identify real vs counterfeit bills.

William, You are right you can print a counterfeit proof of fund's letter and send it to the seller and if the seller requests the buyer for a bank statement to back up the counterfeit proof of funds, then the buyer will need to run for the hills, and now the seller will know that the buyer was trying to pull a fast one.

The most sensitive info you have is your ssn.Another issue is the presentation of counterfeit check, some banks simply charge a fee to cash a two party check, it's a low skill level that I don't have but it's not hard, the issue may be covered but it's a PITA proving it's not your check.Automation is great, makes life easier, but keeping collections away from depository information is the best security, funds come to you and you make deposits.BTW, for the lease-option, installment dealers out there, you can have more issues with any partial payment.

Cash can be counterfeit.

One too many times with my name being submitted to homeland security for depositing counterfeit bills.

Yeah it's called counterfeiting :)-

It's not safe, the money would have to be counted, and I would have to verify the money is not counterfeit. 

FUN FACT: Did you know tenants can buy fake/counterfeit paystubs from the internet or Facebook for $20?