I am new to seismic analysis which maybe the reason I can't quite get my head around snubbers but here goes with my problem.

In my simplified little world if a pipe is sat on steelwork but is not attached nor guided & their is no friction then when the steelwork is displaced rapidly due to a seismic event the pipe will remain stationary.
If we use this simple model & add a snubber when their is a seismic event the steelwork is displaced rapidly which would lock the snubber which in turn transfers the displacement of the steelwork to the pipework.

So either I am totally off in this or we are using snubbers to initiate seismic displacement in our pipework?

Maybe we are getting carried away with things because we model seismic events as forces and forget that the forces are induced by displacements.
Just my little $ worth now I will stand back & get burnt down in flames by illustrious engineers.

The issue at hand is not just the pipe sliding around on steel…. But eventually the pipe is attached to the structure in some manner… maybe a rod hanger, or through a connection to a piece of equipment attached to the structure. In that case then the entire system will be pushed or pulled at that connection point as the structure moves in all 3 planes of direction (maybe even all three simultaneously) Maybe its connected by sliding into another pipe or part of the structure or by falling off a piece of support steel!

Once this happens the lack of seismic restraints on a system causes a crack the whip effect to occur in the piping system. This may cause overstresses. As you have stated you are new to the phenomena I suggest you engage in some independent study as opposed to your current approach, I suggest you start here….

http://www.americanlifelinesalliance.org

in particular read this…. http://www.americanlifelinesalliance.org/Products_new3.htm#RetrofitPiping

As for Snubbers I strongly recommend doing without them, instead them use gapped restraints. But for a beginner to be able to execute the design without Snubbers will be very difficult.

Finally use the search function of this forum you will find a plethora of discussion on this subject matter.