May or May not means that you can use one of designes bb designs at your leisure or you cannot use one of designes bb designs at your leisure. This will always be stated near or around a design. If this is not near or around a design then the design is defaulted as may not which means you may not use the design at your leisure. What does leisure mean in this context? Using the design for profit, utility, general use, casually, with one's own or that of another's intentions good or bad... without guidelines of use from designes bb and  but not always, specific outlined compensation.