Typically situation I don't think you have to worry about it being knocked off or sliding off since it is fairly heavy, think about all the bookshelf speakers on stands out there there are a lot lighter and higher then these sit. But I live in California, earthquake prone. I did have 4 holes drilled on top of the stands to line up with the spike holes of the Gallo. I got some threaded screw type going from the bottom of the Gallo's through the holes so that they don't get shaken off.
Apparently Gallo uses metric threads so I couldn't find any T-nuts to screw their points into so I opted for those spikes. I think in the long run, it's more stable since they have a wider stance.