Additional Fees for Vacation Brokerage

Hello, I would like to ask: I work in a tourism company where the company earns from brokerage fees for accommodation. There are times when the hotel/guesthouse/campus does not charge for a certain service or product, but we offer it for a fee, which comes to us as an additional commission. For example, a hotel where we booked a group and offered the group the option to use the swimming pool for a symbolic fee for each participant. Or another place where we charge extra for linens, even though the place does not charge extra (this refers to places where it is reasonable that some provide the place without linens, not a hotel of course). It should be noted that there is no obligation to take these additional services, and a group can book the hotel without using the pool. Or they can take it without linens, only with pillows and blankets, and the group brings linens from home. I also note that this is not an excessive or unreasonable commission, but it is in addition to the brokerage fee we take for accommodation. My question is: Is there a halachic issue with acting this way? I would greatly appreciate the rabbi's response on this matter. Thank you and blessings,

Answer from our teacher, the Gaon, Rabbi Avraham Fried, shlita:

If it is customary in tourism companies to charge additional fees for such things, then there is no problem.

If there is no such custom, the law depends: if you think that customers understand that you are charging only percentages from the costs and not selling services provided as part of the stay in the hotel/guesthouse, then according to the law you need to inform customers that you are charging an additional fee beyond the brokerage, in the word "brokerage" these things are not included.