Tenant caused a warranty to become void - recourse?

[Emily Stevenson]

I recently had my tenant's tub refinished after she reported the finish was peeling, at a cost of about $450. I told her that the shower couldn't be used for 24 hours after the work was completed, but her boyfriend came over and used it without knowing. The finish isn't damaged, but the company specifically said that exposing it to water before it had had 24 hours to cure would void the 5-year warranty on the glaze.

There's no guarantee my tenant will be around for 5 years. What kind of recourse do I have in this situation? What if the tub chips 3 years from now and I can't make a warranty claim and she has already moved out and gotten her security deposit returned to her? Is there some formula I can use to withhold a portion of her deposit because of the risk of damages after she moves out that her negligence caused me to become financially responsible for, or would my only option be some kind of nightmare scenario where I have to locate her years after she's moved out and take her to small claims court over the cost of the repair?