Return email?

I sent an enquiry email to a guesthouse in combodia, thru their website. At the bottome of the return email was this

Warning: this message was sent without Return-Path.
Ask the sender to correct Return-Path by adding '-f' to send mail script.
This is a sample php code:

mail (recipient,subject,message,'From: sender','-f sender');

I have an gmail account, is this common?

Thanks