Unseating avatars with a linked script

I have a car with a convertible top. It goes up or down by touching it by using the llSetLinkPrimitiveParams function in a script that is in the inventory of the convertible top. The car has two seats and everything is linked together into one vehicle.

The problem is that when there are Avatars sitting in the seats and the convertible top is touched, the Avatars are unseated.

Now I know that changing the Linked Primitive Parameter will throw the Changed Event and the CHANGED_LINK constant in the overall object, but how does that unsit and Avatar on another prim?

I think llSetLinkPrimitiveParams() should not be generating CHANGED_LINK events, which should only occur when the membership of the linkset itself changes. One thing that will unseat avatars, though, is changing parameters (such as "cut" to the PRIM_TYPE of the prim on which they're sitting. I don't know if this also occurs when other prims in the linkset are similarly changed. Changing other primitive parameters like texture, alpha, etc., don't have that unseating effect.

I'm starting to think this is a bug, similar to how changing clothing on a seated avatar used to trigger an unsit, until that was fixed several months back.

Yeah, now that you mention it, it's not obvious why this should be necessary--it sure caught me by surprise the first time I encountered it. So I opened https://jira.secondlife.com/browse/SVC-389 ... maybe a developer will explain why this is desirable.

I know this thread is ancient history, but the jira has been resolved, and I've tried it on a simple example that always failed before H4. It looks like one can now change PRIM_TYPE parameters in a linkset without unseating avatars. Good news for some "transformer" vehicles and self-reconfiguring furniture.