BlackBerry Z10 STL100-2 (aka R086) lists the LTE 7 band, or 2600 MHz, so I assume it is offered by Bell and Rogers, who both offer that band.
Do providers lock out the frequencies not used by their networks?
Yep, North America has STL100-3, STL100-1 for some parts of EMEA and APAC. STL100-2 for LTE enabled countries in Europe and actually even in Asia they have countries that use the STL100-2. STL100-4 is exclusive to Verizon.