As usual, in an effort to win the debate, some little details are not being talked about very clearly.
The first thing I want to say is that if you think that extending the slide, then putting a jack under it and lifting it a few inches is not going to cause any damage.... Read no further.
Because of the way MOST TTs are constructed today, slide supports are generally a high risk/low reward idea.
If you want to use them, then you must make absolutly SURE that the TT itself cannot lower in relation to the slide. This can happen in the case of a slow leaking tire... It doesn't have to go completely flat... As for the jacks holding up the TT in this event... It probably won't work. Most TTs today use scissor type STABILIZING jacks, which are well known as not to be used as the sole means of suupport... And they are typically mounted towards the ends of the TT, which is not where the support would be needed if a tire was to lose air... In order to be effective a jack would need to be close to the axles.. Jayco said that he uses a screw jack.. This is different than the common scissors jack. They are not commonly used any more. This type of jack CAN be effective IF it is used under the frame close to the axles, AND it is on firm ground that will not sink under heavy weight. Think concrete or asphalt here.... And that brings up the other concerns... If one attempts to do this with the factory mounted scissors jacks, which we already know are not meant to support the TT, where they are mounted will not prevent frame flex, which can be a problem depending on how long the TT is, and how strong the frame is... In addition if the TT is not on a pad of concrete or asphalt, then the jacks can easily settle at different rates. My jacks are about 30' apart. The soil can be quite a bit different in 30'... Add some rain and the probability of a the jacks sinking unevenly goes up a lot.
To sum it up... If you want to use slide supports, then in order to be SURE that your TT will not inccur expensive slide damage, then you must make sure that the preceeding issues are addressed... EVERY single time!! The one time that you skip it will likely be the time that you have a problem....
Or you can just rely on luck.
One thing is quite certain... No manufactrer will warranty this type of owner inflicted damage.
