The ratcheting jack stands are completely safe. You can only pull up on the handle if there is no weight on the stand.

I've used a set of these for about 15 years and I trust them as much as I can trust ANY jack stand. Before that I used some that are made of thin wall pipe with a pin. They are no stronger, but they are much less convenient than the ratcheting type.

Hopefully after this weekend I will never need them again. I almost have my two post lift put together and operational.

Good luck,