As with anything else in society, just because nobody SAYS anything, doesn't make it right. Another instance of somebody tending to their own personal needs, wants and desires as opposed respecting the general public.
Oh - and it's against the rules. I know - the rules are broken daily by those who feel they don't apply to them - but it still doesn't make it right.
Walt Disney World Resort Park Rules
GENERAL RULES
Welcome to the Walt Disney World Resort. To ensure a safe and enjoyable experience for all our park Guests, please respect the following rules:
a. All persons, bags, parcels and other items may be subject to screening/security checks at the Park entrances and also within the Parks.
b. We reserve the right not to allow any bag, parcel or other item to be brought into the Parks, and to deal with any unattended object in such way as we consider appropriate.
c. Please show common courtesy to fellow Park Guests and our Cast Members by not using profanity or engaging in unsafe, illegal, disruptive or offensive behavior. For your safety and the safety of others, please refrain from running.
d. Proper attire, including shoes and shirts, must be worn at all times. We reserve the right to deny admission to or remove any person wearing attire that we consider inappropriate or attire that could detract from the experience of other Guests. Visible tattoos that could be considered inappropriate, such as those containing objectionable language or designs, are not permitted. Special events may have additional attire guidelines.