1. For purposes of section 22(b) of the CPA (warrantless search), an officer has reasonable grounds where he receives information from an informer, considers the late hour and distance that would allow concealment of evidence, even if the suspect is unaware of the impending search. 2. For purposes of section 40(1)(b) and (h) of the CPA (arrest without warrant), a police officer properly verifies an informer's information and does not rely solely on it where he questions the suspect and conducts a search that discovers the contraband before arresting. 3. Even where arrest is lawful, an officer must exercise discretion on whether to detain or issue a written notice to appear, considering factors including: seriousness of the offence, quantity of contraband, whether suspect is known to police, time and location, distance to police station, and consequences if found guilty. 4. For leave to appeal under section 17(1) of the Superior Courts Act, there must be a reasonable prospect of success - meaning a sound, rational basis to conclude there is a realistic chance of success, not merely an arguable case or one that is not hopeless. 5. A court is constrained to decide only issues properly pleaded; conduct not pleaded (such as assault) cannot form the basis of a claim even if mentioned in evidence.