I used to work for lawyers and I can hear them in my head saying to keep quiet and don't admit to anything or say you're sorry, etc.If they knocked it off the track and didn't tell you, and that's why it fell, then you shouldn't be liable for negligence, in my opinion. 

Additionally, I'd rather my tenants get a little interest (albeit negligible) than nothing at all.

Worst case scenario is probably you lose all of your investment, and do something negligent that gets you sued for more than the asset.

Even if your lease says "not responsible" that doesn't apply if it is found that your negligence creates the problem.I would just fix it. 

Don’t know if this is fear or concern, but fear of negligence!

If it is due to tenant negligence or misuse then charge them for the repair.

Follow the law, if the law says your contractor can make repairs in a small space then do it, but document it per the law to show that the issue was caused by their negligence and not your lack of maintenance.

We ended up with 8k in repairs/cleaning/water damage due to negligence directly related to their 3 year stay. 

Any costs above $50 will be landlord responsibility unless it is determined to be caused by tenants' improper use/negligence  (example: flushing items down toilet other than toilet paper) Not only have these two lines saved us money but also a lot of driving and avoidance of nuisance calls.

You basically need to "student proof" the home, any little thing you could potentially see causing a problem or being broken by negligence, try to take preventative measures to replace beforehand.