From Blaseball Wiki
Careful is a Player Modification, first seen during the Season β16 Elections via the Alternate Trust Will.
When a Player has the Careful modification, their Items will not be damaged by standard game actions. Items can still be damaged by other actions, such as defending from attacks by Consumers.
The Careful modification first appeared in the Season β16 Elections as the modification granted to players Alternated by the Alternate Trust Will. It has since appeared as a modification on Items.
In Season β16, the following players were granted Careful via Alternate Trust: