I have been flat towing my Samurai since 2005. I have had three different transfer cases due to changing gear ration. I had one transfer case with twin sticks. Not one time did I ever have one transfer case "slip" in gear. Respectfully, when I hear someone say that, I really hear them say they goofed. I did goof once, and towed for about five miles. Actually, I was more stupid than having goofed. The t-case did not "slip" in gear. I was lucky, no harm done.
After hooking up to my truck, I typically will do as skipro3 posted. Then I will start the Samurai, with the transmission in second, put the t-case in gear and slowly let out the clutch. I expect it to feel a load on the engine. Then I will put the t-case in neutral while the engine is running. Let the clutch out if the engine doesn't die, you are ready to go. Turn the key to its proper position.
I removed everything wired on the accessory position of my ignition switch. This allows me to just turn my key to the Acc position to unlock the steering wheel for towing.
It is not unusual for me to open the hood of the Samurai and look at the position of the writing on the fan belt, or even have someone look at the fan while I pull forward a couple of feet. If the engine turns, the t-case is not in neutral.
More often than not, I use my Samurai as a trailer. I use care not to load it in a way a bump or something can change the position of my transmission or t-case shift levers.
Should you not be aware, DO NOT HAVE SOMEONE TRY TO HOLD THE STEERING WHEEL WHILE YOU BACKUP. You most likely will break their thumbs.
Wayne
2004.5 Ram SLT LB 3500 DRW Quad Cab 4x4
1988 Bigfoot (C11.5) TC (1900# w/standard equip. per decal), 130 watts solar, 100 AH AGM, Polar Cub A/C, EU2000i Honda
Toad: 91 Zuke