Where did you find this information?
Have you been charged with something?
In Canada summary offences are referred to as summary conviction offences. As in other jurisdictions summary conviction offences are considered less serious than indictable offences because they are punishable by shorter prison sentences and smaller fines. These offences appear both in the federal laws of Canada and in the legislation of Canada's provinces and territories. For summary conviction offences that fall under the jurisdiction of the federal government (which includes all criminal law), section 787 of the Criminal Code of Canada specifies that, unless another punishment is provided for by law, the maximum penalty for a summary conviction offence is a sentence of 6 months of imprisonment, a fine of $5000 or both. Section 786 of the Code has a statute that prohibits persons from being tried for a summary conviction offence more than 6 months after the offence was committed unless both the prosecutor and defendant agree otherwise.
As a matter of practical effect, some common differences between Summary Conviction and Indictable Offences are provided below.
Summary Conviction Offences
Technically, yes you can be arrested without being charged or being told the charge. When you're arrested, it's on suspicion of a charge. It's the crown attorneys that actually lay the charge most times, except in lesser offenses as you've observed through your own research.
Indictable crimes, drug offenses, terrorist activities, the bigger crimes are most common for arrest without charge.
Whether they can is different from whether they will or whether they have, and my opinion sitting here isn't going to change what has or will happen.
Don't forget that many offenses are hybrid offenses, and so can be either pursued on a summary or indictable basis. That's up to the crown. The police rarely make these distinctions anyway, if they have personal evidence to formulate an arrest they usually do so, if they have statements that lead to an indictable charge if reliable, they get a warrant. They do what they can to get the arrest and then let the crown sort it out.
If the arrest was improper, your lawyer can make a pitch to have it thrown out, and likely succeed.
It might have been a hybrid offense. And again, whether I agree with you or not that won't change what happened and what your options are from here on in. Get a criminal lawyer to look at it and determine if it's worth trying to have the charges quashed or the evidence gathered as a result of the improper arrest thrown out.
It's common for police to arrest on minor charges and gather evidence for the crown to review and consider whether indictable offense charges can follow.