I got the feeling in your post that you were trying to down play any guest incidents.

It is a good idea to have at least $1M general liability policy on your rental in case of injury or incident.

They are likely putting that policy in for this reason after who knows how many incidents like this, probably at the behest of whoever underwrites AirCover. 

I ended up buying a professional snake (one of those thousand dollar+ jobs) from a retiring plumber for $400 that I talked down to $200.I did used to pay for professional servicing, in fact had jetting/cutting/camera done just 6 months prior to this incident which I now think half of the job wasn't even done at all let alone correctly.

Similar incident at one of my units, but we (HOA) called a gate company and had them out there within a hour removing the gate so the garage was still useable.

If it is only from the incident , it would be the water that was left running during the time that the incident occurred.

I don't let outlying, relatively insignificant issues cause me to reject someone that has either clearly changed their life (as facts illustrate), or simply had a couple incidents of poor judgment.

What kind of claim do you want to make and what is the date of the incident?

.)), affd. 852 F.2d 306 (7th Cir. 1988).”and “We believe the record in this case, although sparse, establishes that B'Mae's (the management company) was acting as petitioner's agent when it undertook the various activities incident to renting out the timeshares.

Very likely they will be able to look up a log of all "incidents" recorded on that specific sign.