I wouldn't send any money in advance. I hear from our friends and clients that the landlord/agent ask them to send them money. The reasons could be that they are out of town , deposit the check and then pick up the key later. Some of the worst one that an individual shows the house to many renters take deposits from many of them and he/she even not authorized to rent the unit.
I hope this helps.
I would always be careful of anyone who requests money up front from you, whom you don't know or have any type of relationship with, and who states that they will return money back to you after anything especially on line.
There are just way too many scams that I am aware of in real estate of people demanding money up front either as a security deposit before viewing, a deposit on a property that they don't own (this is especially true of some short sale or foreclosed properties where they may be unoccupied and some person pretends to own the property), wanting a money transfer because the owner is out of the country, etc.
Often the scams are associated with properties listed well below market rents or market value which is a good way to identify them. If something seems too good to be true it usually is and should raise red flags. There are exceptions, but they are rare. Usually if it is some great deal people are more likely to offer them to friends or people they trust then post it online.
Always check public records for who the owner is before giving money to anyone. You always want to make sure you are dealing with the actual owner.
Best of luck
GB and Associates
Cell (415) 640-4341