An interesting, albeit brief, answer to this question in Losing the Signal, pg 210-211:
A senior official from Egypt’s telecommunications regulator had just called to deliver an ultimatum, she said. State-owned Telecom Egypt had yanked the plug on BlackBerry service in the country, and it would stay off-line until RIM handed over encryption keys for coded e-mails and messages traveling through Egypt over RIM’s secure network. As his car moved through the snow-quilted streets of Davos, RIM’s boss struggled to make sense of what was happening. What did a phone maker from Waterloo know about tyrants and revolutions? “I’m shitting my pants,” Balsillie says, shaking his head, remembering the stress that night. “I didn’t take this course in business school.” Balsillie did, however, understand that by allowing Egypt to decode encrypted BlackBerry messages he could be giving up protestors who relied on BBM messages to coordinate covert activities. “I didn’t start a tech company to help totalitarian governments kill protestors,” Balsillie told Bawa.
From pg 211:
Saying no to the Arab nation meant kissing good-bye to one of RIM’s fastest-growing markets, a loss it could ill afford as American customers retreated from BlackBerrys. But the financial hit and shareholder anger couldn’t be as bad as aiding and abetting execution squads. After several back-and-forth calls, Balsillie arrived at a decision. “We’re out of Egypt now; we’re not doing it,” he instructed Bawa. As it turned out, Balsillie would never have to explain his decision publicly. The next afternoon, the desperate Mubarak government ordered Egyptian carriers to shut down, blocking everyone except the country’s stock exchange from Internet access. “We dodged a bullet. BlackBerry was no longer singled out,” Balsillie remembers.