Landlord and tenant should negotiate whether they will request waiver of subrogation clauses in their property insurance policies, liability insurance policies, or both (it is less common for the parties to request waiver of subrogation clauses in liability insurance policies, but possible).
Since Nick's answer covered average speed over the entire lifetime of the bike, I'll cover the average over time spent moving. Simply put, this depends almost entirely on the cyclist, rather than the bicycle itself, and there is a wide range. Casual recreational cyclists probably average around 10-15 km/hr (6-9mph). This is your weekend trail rider, out to enjoy the view in the local park.
Examples from the Web for average speed Expand Contemporary Examples Between 1980 and 1990, the average speed of a Tour de France rider was 37.5 kilometers per hour. The distance under steam was 966 knots, and the average speed 65 knots. Her average speed was nine knots, but with a fair wind she did eleven. Thus the average speed of the steamers is about 254 miles per day. Then they began to tow at an average speed of four knots an hour.