Well it has happened to me a few times even with new straps. I still like the stand because of its comfort level and how quiet it is but it is not as solid as I like and I am 6' 2" , 250 pounds so that may make a difference.
Well it happens. Especially on say a oak tree. It may would hold a little better of a pine. Either way the top strap that hold it to the tree is a rubber coated cable. It does not dig into the tree. It is solid when you are sitting but once you stand up the top section is not solid. Tap it from the side and it will shift. It is personal preference though. There are good and bad things will all stands. My favorite is all aluminum with teeth that dig into tree. It is heavier and not as quiet as my Viper SS but it feels a lot stronger in the tree. I fell 2 years ago from 20 feet out of a climber so feeling safe up in the tree means a lot to me. I don't think anything would happen to me in the Viper but the other just feels safer IMO. Everywhere it touches the tree has metal teeth dug into the tree.
Summit Goliath here. I'm not a big person, 200 lbs and 6'1" but I love the extra space. I have had problems with my Summit slipping on some oak trees as well. The teeth don't seem to dig in as good as you would want. You just have to be careful of what tree you are attempting to climb. Best tree to climb in my experience is a Walnut tree. The bark is soft, quiet and allows the teeth to dig into the tree. Takes a lot of wind to get me antsy when I'm in a Walnut tree as well.
i have an older summit viper, its fine but dont have any intensions on using it over my tree saddle this year...jmo
Just curious but do you use the additional strap that is suppose to go around the tree and the top section? This strap also doubles to hold the 2 pieces together when it is packed together for carrying? This may be the reason you are having trouble with it coming loose. The comment above makes me ask you this question, because the additional strap is not rubber. I've attach a pic of the strap I am talking about. Here's a link to the strap on Summit's site. http://www.summitstands.com/productdetail.aspx?id=329173
I do not have a strap like that. I do not remember one being in the box either. Like I said it doesn't happen often. I usually try to find Pines to climb with but I could probably just buy a ratchet or cam type strap and sure it up. Thanks.