If your only concern is the tablet being knocked off the stand, you should just put velcro tape on the tablet and the stand. Then it will be very stable.
If course, if your concern is the entire stand being knocked over, there is nothing (short of cementing the stand to to floor) that will be guaranteed to prevent that from happening.
Your Manhasset stand is probably pretty heavy duty. So, it shouldn't be knocked over too easily (and if the tablet is velcro'd onto the stand, it should not be knocked off the stand).
I hope this helps.
Of course, if you want something that does not block you as much as the Manahsset stand, I like this: http://www.amazon.com/gp/product/B000OR7...detailpage
Jeff
If course, if your concern is the entire stand being knocked over, there is nothing (short of cementing the stand to to floor) that will be guaranteed to prevent that from happening.
Your Manhasset stand is probably pretty heavy duty. So, it shouldn't be knocked over too easily (and if the tablet is velcro'd onto the stand, it should not be knocked off the stand).
I hope this helps.
Of course, if you want something that does not block you as much as the Manahsset stand, I like this: http://www.amazon.com/gp/product/B000OR7...detailpage
Jeff