Has that been recently? The leases I've seen have been signed within the last 18 months and have drilling operations clauses attached to them.
These were both on acreage in N. Okla East of Enid with two different land owners. Turns out, the land owners knew what they were sitting on, and wanted immediate production and didn't want to bother with someone who'd lease land just to have it, but not drill it till later.
This may not be a standard practice, but I know they were a trendy proposition for some of the more savvy land owners.