Ghibli Museum made an announcement on their official website on March 1st that they will revise their ticket system starting June. From the tickets sold on Jun 10th (for July admission), the tickets will indicate the purchaser’s name. Following this change, from July, the museum may be checking the ID of the guests before entry.
Entrance to the Ghibli Museum is by advance purchase of a reserved ticket which specifies the appointed date and time. Since they limit the number of tickets sold for each slot, it is still difficult to purchase them even after over 10 years from its opening. Because to that, the tickets are often sold on the internet for the higher price than the actual. It seems that this new rule has been applied to avoid people from scalping the tickets.