According to a report from Kyodo News, citing official Japanese government documentation, Sony Computer Entertainment knowingly delayed telling the public about the extent of an attack on its PlayStation Network so as not to "bewilder" its customers.
The report, submitted to the Japanese government and obtained under a freedom of information request, says that SCE was able to confirm internally on April 25 (American time) that a "fairly large amount of data" had been exposed to hackers. A press release issued the next day, however, only stated that Sony could not "rule out the possibility" that personal information had been compromised.
It's also claimed that PlayStation boss Kaz Hirai gave incorrect information in a statement issued on May 1, in which he said Sony didn't learn about the extent of the attack until April 26 (American time), a full day later than the company confirmed matters internally.
The official document also says that Sony delayed informing the public of the extent of the breach so as not to "bewilder" its customers, a spokesperson saying "We hadn't figured out (at that time) what kind of data had been leaked. If only passwords and IDs (were breached), they cannot be considered personal information, and so we didn't want to bewilder our customers."
While being out by a day seems minor, that discrepancy combined with the gap between what Sony knew internally and what it told people publicly still raises the possibility - and this is why the Japanese government is looking into this - that, as Kyodo News puts it, Sony "deliberately attempted to downplay the seriousness of the situation by not fully disclosing information".
Sony knew data breach was massive but withheld full disclosure [Kyodo news, subscription required]