I am 16 and the situation was that I was making a map of my school's security cameras (I was pretty bored) and one of my teachers saw me working on it and reported it to the school authorities. They called me into the office and asked me if I had a map of the school's cameras and I replied yes. They then told me that they were going to search my bag which I replied they did not have any sort of consent to search me, and since I had broken no laws, I thought since they didn't have any probable cause or reasonable suspicion, they couldn't search me. They then called my parents and asked to search my bag and they gave consent and they went right ahead with the search. Is this really something that they can do? Would the same thing apply if they were attempting to search my body?
The school admins likely did not even need to call the parents to obtain permission to search the bag. School admins only need reasonable grounds to believe there is evidence of a crime. This lower bar is due to inherent nature of the school environment and what it takes to manage it:
How, then, should we strike the balance between the schoolchild's legitimate expectations of privacy and the school's equally legitimate need to maintain an environment in which learning can take place? It is evident that the school setting requires some easing of the restrictions to which searches by public authorities are ordinarily subject. The warrant requirement, in particular, is unsuited to the school environment: requiring a teacher to obtain a warrant before searching a child suspected of an infraction of school rules (or of the criminal law) would unduly interfere with the maintenance of the swift and informal disciplinary procedures needed in the schools. Just as we have in other cases dispensed with the warrant requirement when "the burden of obtaining a warrant is likely to frustrate the governmental purpose behind the search," Camara v. Municipal Court, 387 U.S. at 532-533, we hold today that school officials need not obtain a warrant before searching a student who is under their authority.
New Jersey v. TLO 469 US 325 (1985).
School searches are upheld when they are reasonable. To be reasonable, the search must
(a) offer a moderate chance of finding evidence,
(b) the way the search was conducted was reasonably related to the search's objectives, and
(c) with respect to the age and sex of the child and the nature of the rule the child violated, the such must not be excessively intrusive.
New Jersey v. TLO.
Conducting a search that reasonably relates to the search's objectives means if you suspect someone of shoplifting a TV, a full body search may be considered excessive. while a flat-handed patdown to check for weapons when approaching someone as a police officer is almost always found appropriate.
"Probable cause" and "reasonable suspicion" are things that apply to law enforcement, not private authority.
Your school may also have conditions of entry that include, or be in a jurisdiction with laws that specifically allow, search of student persons and their property under some given circumstances. This may or may not involve police to ensure a search is conducted appropriately. Your consent is not required in such cases.
Finally, your parents may consent on your behalf, especially if you are defined as a child or young person over whom they have this authority. For students considered legal adults, this is like to not be a factor.
It is not illegal for someone to search my bag or even my person if I give consent. As a child (which you are until 18), consent given by your parents is consent given by you.