Theres a limit.
While there are currently no annual contribution limits, you can receive the Canada Education Savings Grant (CESG) only on the first $2,500 in contributions per year, or up to the first $5,000 in contributions, if sufficient carry forward room exists. Any contributions over and above these amounts will not receive any CESG for the current year or any subsequent years. All contributions exceeding $50,000 limit will not attract any grant even if the maximum $7,200 of grant is not reached.