Yes, but it depends on how much you want to lift.
If you lift high, make sure the two stands you had already put, don't tip when you lift for the other two.
If they start tipping, you can lift in stages -- lift all 4 corners half way, then again. Same thing when lowering down.
If you aren't sure about the stands stability, wooden blocks would be safer.

Care should be taken anyway:
It is 'tempting' to lean above the handle, but never do it.
NEVER have your face or armpit above the handle.
You don't want to make your Jeep miss you until you get well... :)

What is the discount code so I can grab one too? Thanks in advance

Had to go back and research the article again. This information is in the comments section:
Overland Expo - Overland Tech & Travel - Transform your Hi-Lift*jack

"What I can do is extend a $69.00 price to your readers through the end of February. They will have to use discount code "OVERLAND" when they place their order for the 51M-SJS Safe Jack Stabilizer."

For that price you can buy a welder at harbor freight and the steel to make it.

def cool but not cost efficient haha

Medical bills and rig repair bills for body damage from fallen jacks aren't cost efficient. This device greatly reduces the chances of receiving either. Sounds like money well worth it to me. ;)

Other SAFE JACK accessories for the Hi-Lift JAck
 

Einstein said,"Everything should be made as simple as possible....but not simpler." The Safe Jack products by Bogert Manufacturing seem to do just that. They make things simple and that's the tough part. Besides the stabilizer base plate, they have a couple of other useful tools. I know some off road professionals that are using this stuff and I know that some of it will be going on the next Camel Trophy race. Check them out on you-tube by searching "safe jacks". Jonathan Hanson of Overland will be teaching a class on the Bogert accessories during Overland Expo in May.