Mewborne Oil Contacting Remaindermen

Our family owns 20 nma in Section 33, T17,R 16W. We are not currently under any lease. Mewborne Oil recently sent informal lease offers to my children, a niece and a cousin who is a remainderman. Is this a common practice? Are they just trying to fill out the family tree for the future or is this predatory behavior? The varied options seem very low, also. $800nma & 3/16; $600 & 1/5; $0 & 1/4. I have put in a call and an email to the Landman.