Legal Question in Real Estate Law in California

Re: prescriptive rights

The short answer is yes.

Assuming by "prescriptive rights" you mean an easement obtained by prescription, such an easement ordinarily attaches to the benefitted parcel and when that parcel changes ownership the easement goes along. There are exceptions, one of which is when the benefitted and the burdened parcels fall under common ownership, or possibly where the new ownership of the benefitted parcel makes substantially different use of the easement.

In short, once an easement by prescription is obtained, it is difficult to erase.

An easement by prescription is obtained by "open, notorious, continuous and hostile" use for five years, in much the same way adverse possession establishes ownership. If the use is made with the owner's tacit or explicit permission, the element of hostility may not be present and the easement will not arise in the first place. The continuity requirement is still met (usually) if there is an intervening change in the identity of the user, as where X sells to Y after three years and Y uses the space for the remaining two years needed for the easement to arise.

The example you give, however, does not describe a situation in which prescriptive rights were or are being obtained in the first place. The key word is "allowed." This suggests the parking of the RV or boat is with permission. If so, the required "hostility" is not present and no easement will arise.

The legalese of easements gives terms like 'hostile' somewhat technical meanings. "Hostile" here does not require personal animosity; it just implies that the use being made is adverse to the owner's interests.