Andrea Tornielli of La Stampa writes that the Vatican had deployed sophisticated anti-bugging technology in the Sistine Chapel and throughout the apostolic palace in the days leading up to the conclave. The anti-bugging measures were already in place during the general congregations at which cardinals exchanged ideas prior to the opening of the conclave. Reporters who were in the building testified that internet connections were interrupted and cell-phone signals lost when the system was activated.
Found it interesting that they have a system that they can activate on will, not just a permanent Faraday cage or something.