No, this type of arrangement dates back to the 1860's, and is about as ironclad as the Northwest Ordinance. They ALL do it, it's managed by the FRA, and it's stood up to many lawsuit attempts. It's done taht way simply because it's cheaper. Imagine how many routes Amtrak could run if tey also had to pay liability risks to the host railroad.
In the 1940's, SP wrecked a streamliner on Rock Island spring switches; SP had to take full liability.
In the 1910's, the Pere Marquette ran a passenger train into a LS&MS train near Chicago. They ahd been feuding over who had "right of first crossing" (which determines who dispatches and who has ROW). Since PM was the tenant, even though they were "right", they paid. . .
Most recently, several years ago CSX was found negligent in a wreck where an Amtrak train derailed on an improperly reassembled switch. It was a multi-million judgement, and siince Amtrak was the tenant, they wrote CSX a check for CSX to send on to the plaintiffs.
Sure, these are examples of where the tenant was in the right, but there are far, far more where the tenant was wrong (broken axles, and the like). It's just that THOSE stories aren't as interesting.