Tom Holland - Spiderman Actor

[Fred]

d warned his successor to have a fly installed on the new iteration of the costume.

A visible fly would spoil the image of a superhero. In the comics they never peed, and if they're so darned super, surely they also have super bladder control!

[googlism2008]

Well in the case of Batman, the website said,

This isn't the first time that a superhero actor has complained about bathroom problems associated with their role. Christian Bale aired similar grievances about his Batman suit while filming The Dark Knight trilogy. The Nolan Era Bat-suit became so problematic that Bale even spoke to Ben Affleck before the shooting of Batman v Superman: Dawn of Justice, and warned his successor to have a fly installed on the new iteration of the costume.

Apparently George Clooney did pee in his batsuit.

A visible fly would spoil the image of a superhero. In the comics they never peed, and if they're so darned super, surely they also have super bladder control!

It would be interesting to consider characters with superhuman abilities in some aspects, but not all. Perhaps the superhuman abilities doesn't include a supersized bladder and a super bladder control.

Or alternatively, the superhero has a supersized bladder and a super bladder control. Having said that, even though the superhero can put off peeing for much longer compared to ordinary humans, the supersized bladder capacity is still finite, and there is a limit to the super bladder control. With a superfull bladder putting way too much pressure, the super bladder control might ultimately crumble completely. The result could be a supersized flood.

Or perhaps something else simply happened. A momentary lapse of concentration, perhaps. Batman did have a "bladder spasm".