Secret Surveillance
Most of the meetings with other objects do not seem to touch and affect a physical body in any way. Photons, as the assumed particles of light are called, and other quantum objects are meant to bomb it all through its lifetime — without any noticeable impact. That is one reason why observation is possible: it shows the things how they are, leaving them untouched.
In this sense, observation effectively does not take place, it is not existent, so to speak. And so, because it carries no weight, it can take place all the time.
In fact, physical events, the motions of a physical body, for example, are treated as being wholly observed. That means, as having at every distinct time at a precisely distinct place a distinct velocity (and so on). Every state of that object is completely defined — may this conception be practically realizable or not. The object is the sum of its defined states or appearances, which are thought to be infinitesimal (that is: of infinitely small extent). They make up its existence.