Well yeah if you throw a 3 foot long lens on it and cantilever it out straight forward without doing anything special, it will drop.
There are a ton of tricks though. For example, if you have a huge lens, you can put ALL THREE feet facing forward under the lens, and it will usually hold. Sort of like a rocking chair (but since it's knobbly it won't actually keep rocking).
You can also take a little piece of plywood or whatever and one of those pipe constrictor metal things with you and essentially make a lens collar type thing - where the weight is transferred some distance forward of the normal camera mount, to make it more even and not all hanging off one side.
Once you get the hang of it and with a little creativity, the SLR zoom gorillapod can hold stupid amounts of weight. As in like any possible lens that any of us could actually afford.