You can rent via using your points to make a reservation in someone else's name; that is called renting your points but what you rent is actually a reservation not points. Though they may not necessarily be stated in the rental contract you sign, the applicable conditions are that the renter is subject to the same rules as you are in the use of the room and resort (e.g., he cannot hang towels off the balcony either), the renter does not get any DVC discounts, and you can be ultimately responsible for any damage done to the room by the renter or for the renter's failure to pay his bill at the resort.
You are prohibited from transferring points to another member for monetary value. That applies only to actually transferring points not to rentals where you use your points to make a reservation in another's name. One possible reason for the transfer rule is that the transfer transaction actually makes Disney the middleman to carry out the transfer between members and if something goes wrong it does not want to be in a position of being sued by a member for loss of any funds due to a faulty transfer. Another and more important reason for the rule is so Disney can maintain consistency of the contractual rules applicable to points. The offical documents declare that points themselves have no monetary value. The thing you have of value is your real estate interest in the resort which you can rent. Points are deemed to be merely symbols that represent your ownership interest. Thus, to maintain that concept, the offical documents also disallow members from transferring points for monetary value because points are legally deemed to have no monetary value. Despite the prohibition against transferring points for value, many do it, and Disney to date has not taken steps to end that practice, probably because it has accomplished what it wants to accomplish in that legally no one can ever actually claim the points have a monetary value or blame Disney for a monetary loss due to a faulty transfer.
The offical documents prohibit you from renting for "commercial purposes," a vague term which is stated to include a pattern of rental activity that Disney in its discretion determines is being done for commercial purposes. That basically means you cannot be in the busines of renting. In the mid-2000's some rather daunting problems arose with professional renters. By then, the use of the internet had led to making it easy to find renters. Also, the transfer rules at the time allowed an unlimited number of transfers one-way, i.e., you could transfer points in as many times as you wanted to in any year or, alternatively. transfer out as many times as you wanted to in any one year, but you could not do both. Also, members could make anyone an associate member of their membership who could then have access to their account to make reservations. Any single member could own no more than 2,000 points at one resort, and 5,000 total, but any combination of people, such as five friends could together own 5 times as much.
Those factors led to the creation of professional renters -- groups of owners who never used their points for their own trips but together owned large numbers of points; they also got themselves made associates to many other contracts by members who wanted to rent some points; they also agressively sought transfers of points from members. What they did with all the points they controlled was rent reservations and a number of them used large numbers of points to do predatory reserving of huge numbers of highly desirable rooms at exactly 11 months out for high DVC demand times like Christmas and other holidays and early December, and then offering on the internet to rent the reservations they already had. Disney decided to resolve that problem. It went back to the original transfer rule that allowed only one transfer in or out per year per member. It issued a rule allowing one to be an associate in no more than four memberships, and it issued a guideline that provides that anyone who makes more than 20 reservations in any one year will be presumed in violation of the commercial purposes rule and will not be allowed to make any more reservations without first showing that none of them are rentals.
That did not completely eliminate professional renters, but it took the steam out of them and any predatory reserving issues are now miniscule compared to what they were in the mid-2000's
As to whether you tell MS you are renting, the documents say you are supposed to but MS has proven to be a problem because it has far too many employees who appear to know less about the rules than anyone. Thus, you get reports about how an MS resprentative, when told the reservation is a rental, refused to do it because rentals are prohibited. Thus, you face the hassle of insisting on talking to a supervisor, and even they do not always know the actual rules. It is a sad situation caused by Disney that has resulted in many not telling Disney a reservation is a rental when it is.