I had a similar incident in August that resulted in an unscheduled overnight layover due to potential misconnect on last flight of the day at DAL, all due to mechanical. I sent a letter with the details to customer service in DAL, hoping for at least a voucher, or an explanation if they felt that they were not liable for any LUV. I didn't even ask for hotel reimbursement. No response at all thus far, not even acknowledgement of the letter. Obviously it no longer the Southwest of old, but then we already knew that unfortunate fact.