The prevalent use of the Taser, in my view, is unconstitutional under the Canadian Charter of Rights and Freedoms, which states in Section 12: "Everyone has a right not to be subjected to any cruel and unusual treatment or punishment. ..." [LINK]Many taser deployments are clear cases of exactly that.
Especially those that involve the use of the taser in "pain compliance" mode (a.k.a. Touch Torture mode, Drive Stun mode, Dry Stun mode).
Also, repeated taser-torturing of those that are incapable of obeying shouted orders.