They might then encourage the person to go home and carry out an attack -- without giving him any training or access to higher-up specialists that might compromise their local operations.
Drainage could compromise the smooth appearance with guttering and pipes, or it could encourage chronic leakage over time if holes had to be made in the structure.
Compromise and give-and-take between factions allows the organisation to operate without having to satisfy the whims of many different, uncompromising individuals who might otherwise cause a split.