If they are transporting my Mom somewhere and there is an accident, Mom would only be entitled to whatever their auto insurance will pay for her injuries, rehab, etc., and would be prevented from suing the home or any employee, even if it was their fault.
Another issue is that if you do sign this waiver and your mother is injured, her recourse is subject to interpretation by the AL's insurance carrier, generally, in its sole judgment.
So the AL staff should also tell you who their carrier is. If it's one of the ones that are noted for aggressively attempting to limit payment, I definitely wouldn't sign. You could get into the issue of whether or not your mother was injured seriously enough for treatment, for rehab, etc.
And God forbid the injuries resulted in permanent disability, recovery on that would be capped as well. You wouldn't get any compensation for that limitation.
Personally, I'm offended by these kinds of waivers, as what they essentially do is limit their own liability for their own interests.
On the other hand, there's the practical issue that if your mother were injured and sued, any recovery would be subject to actuarial standards, i.e., her age, average expected life, etc.
If it were me, I wouldn't sign, but then I also won't sign pre-employment requests for access to my credit file. Those requests are wide open in terms of liability and in my opinion should be made illegal.