submit offer before due diligence?

[Bao Nguyen]

hello everyone.

I am about to make an offer on a duplex, and I asked the realtor for the rent roll, the credit and background checks on the current tenants, and list of expenses.  I was on the phone asking A LOT of questions to the realtor, and his response was "put in an offer, and you have a period before closing to do your due diligence, and if you find something you don't like you can ask for a lower price or back out".

Can I put in the offer contract that my offer is contingent on the current tenants meeting my standards?  I've not heard of this kind of contingency before (most contingencies are from home inspections revealing infestations or crack foundations..etc) and wonder if anyone has done or heard of such things.   

So is this realtor playing right or is he trying to get me to commit into something I can't easily back out of if I don't like what I find out about the current tenants?