Can the Board/HOA Rent out the Only Extra Parking Spot?

I am on the Board of a small - 17 unit condo building in California. Several years ago (about 1999), a one bedroom unit (with 1 assigned parking spot) owner made an informal/verbal arrangement with the then Board to rent the one and only extra parking spot in the building for $30/month. When the unit was sold, the new owners assumed that same arrangement. The current Property Mgt Company has been billing this owner the $30 monthly fee on their HOA dues bill for several years. One of my fellow Board members approached the owner of the unit and asked if they could park their second car there exclusively since they were now not using it. They allowed this. None of this was disclosed to the other Board members or other home owners. As a Board member, I would assume he had an obligation to disclose this to at least us - the other two Board members? Until I located the buildings original parking grid, I never knew we had an extra parking spot. Now I have learned that the one extra parking spot has been rented for several years and now exclusively occupied by a Board member. This in essence took away the opportunity for every other unit to use what is rightfully theirs for several years. We have also lost out on several thousand dollars given the $30 monthly rate has NEVER been increased. I've been told the market rate would be about $150/month now -- if it was allowed to be rented out (and that the Property Mgt Company had a fiduciary responsibily to make sure we are bringing in the appropriate amt). When I asked our Property Mgt Company why this income was never reflected in the budget they prepared for us/sent out to all homeowners, they said they didn't know about it (despite being the ones to bill and collect the $30 monthly fee and despite it appearing on our cash flow statements.). This same Property Mgt Company and Board member have simultaneously told us we need to raise our HOA dues because we are not covering our expenses. Does anyone have any insight on this issue -- what CA law allows a Board or HOA to do (are we even allowed rent this pkg spot out if the HOA decided to?), what the obligations of the Board member are in this aspect? What the obligations of the Property Mgt Company are in this situation? I would think at a minimum they had an obligation to disclose this on the budgets and advised us that this rate should be at a current market value? And how could this have all been done with out the Board's knowledge or the other homeowner's approval? Thank you.

Thanks Jeff - appreciate your response. I am getting conflicting information however. I fully understand that two owners can make a private arrangement between parking spots they own and have a right to, but this was the building's extra parking spot. It therefore belongs to all the tenants. I'm trying to understand if the owner and the then Board had any right to enter into an agreement whereby an asset (common property) belonging to all homeowners was then rented out for one unit's exclusive use should have ever been allowed. Wouldn't all the homeowners have had to vote and agree to allow this to happen? Isn't it like renting out the common area backyard or pool for one unit's exclusive use without getting all the homeowners agreement? They all own a portion of this one extra parking spot. Furthermore, there was no formal/written agreement w/ provisions. It was merely an informal/verbal agreement on a month to month arrangment. Wouldn't the current Board or HOA therefore need to re-vote on this arrangment to keep it valid? I've been on the Board (and a past President) for 5 years - it has never been brought to my attention. When you mention that the Property Mgt Company has a responsibility to carry out the decisions of the Board I understand that, but there was never a decision from this Board to have this arrangement. (I don't even see any documentation from past Boards that they ever approved it.). Thanks again!