Not quite. GET is defined to be "safe" and "idempotent", and while "safe" does mostly mean "no side effects", it actually means something more like "doesn't cause harm" per-RFC7231:
Request methods are considered "safe" if their
defined semantics are essentially read-only; i.e.,
the client does not request, and does not expect,
any state change on the origin server as a result
of applying a safe method to a target resource.
Likewise, reasonable use of a safe method is not
expected to cause any harm, loss of property, or
unusual burden on the origin server.
This definition of safe methods does not prevent
an implementation from including behavior that is
potentially harmful, that is not entirely read-only,
or that causes side effects while invoking a safe
method. What is important, however, is that the
client did not request that additional behavior and
cannot be held accountable for it. For example, most
servers append request information to access log files
at the completion of every response, regardless of the
method, and that is considered safe even though the
log storage might become full and crash the server.
Likewise, a safe request initiated by selecting an
advertisement on the Web will often have the side
effect of charging an advertising account.
Of the request methods defined by this specification,
the GET, HEAD, OPTIONS, and TRACE methods are defined
to be safe.
