It seems you are referring to a situation where “title failure” implies the Lessor did not own any of the interest. However, would there be the same result (refund of bonus paid) if there was a miscalculation on acreage by the landman? In other words, a Lease was struck and bonus payment made for 40 net acres then later (say 2 months or 2 years) it’s determined the Lessor only owned 30 acres. Would the law require the Lessor to return a proportional amount of the bonus?
Even IF you struck the warranty provision in the lease, you are still bound to return the money. There is an unpublished case just like that and I will look it up and post it here.
The covenant of seizin, when there are words of grant (such as the grants, lease, sets over, etc in the lease) promises that you have the authority to lease.
Striking the warranty does no good to allow you to keep the bonus money. You would need a broad disclaimer to do that, which states that any monies paid will not be returned in the event of title failure.
Best of luck,
Buddy Cotten
Mineral Manager