'The statement from TfL [Transport for London] said it appreciated “the sentiment of encouraging people to wear face coverings”.
“We’d like to offer Banksy the chance to do a new version of his message for our customers in a suitable location,” it added.
The BBC has asked if the travel authority worked with Banksy on this artwork and, if not, whether his actions posed a security risk.’
Since the Tube (and buses) are plastered with exhortations to wear masks, it is compulsory, the only spaces that are compulsory at the moment (with about 70% take up from observation) I disagree that “they” are trying to cover up the message.