Condo owner wants reservation fee for inspection?

I am looking at some different apartment/ condos and someone I messaged has told me- "you'll make a reservation fee of 2000 baht So the unit i'll be out of the market and inaccessible to other clients the fee is a refundable fee either you like the house or not you'll be refunded back' I said I don't need it to be off the market and I can just inspect tomorrow but he is saying it's the only way to go forward, I don't feel comfortable sending money for a place I haven't seen yet, is this normal?