Work that encourages and relies on participation will often be subverted by the participant; they won't do what is intended and the results of their actions will diminish the initial 'reason' for the piece, making into something else. It is common for the particpants activitity and the results from that to be the work and outcome so whatever they do is intended and desirable. Generally though there is some form of guidance, some barrier or line that should not be crossed by a particpant. This might simply be a restriction that manages us in everyday life, such as 'no fighting' or something more intrinsic to the work like 'don't touch' or 'do touch here'. Any rules or instructions that are made in order to facilitate the functioning of the work will probably be where most participants split from their intended actions. At this point if the work does not 'allow' this then there is an anxiety and a frustration emerges between the participant and the work.
Interactive installations often result in behaviour that is unintended, a perfect example of this is Olafur Elliasson's Sun at the Tate turnbine hall. His intention was for viewers to 'harness the precarious and fleeting aspects of the natural world''. They did, but they also had fun interacting with the mirrored ceiling. The sun was created as a semi-circular light with a mirror along the diameter so that it appeared as a whole circle. This mirror created a ceiling covering the whole of the main turbine hall and it was this that made people sit and interact as they did. This youtube video shows particpants lying on the floor of the turbine hall in the warm glow of the sun, but what got them staying there was the activity of placing their bodies in positions together to create shapes and words.

It is quite hard to find much information about how the viewers interacted with the piece, there is no real mention of it on the Tate website. I did find these series of images from another site but there is little evidence on the web. It isn't inconceviable to state that this playful activity with the mirrored ceiling had a powerful resultant effect on the atmosphere in which the piece was received. The playful activity allowed participants to engage with the space, to lie on the floor, to be energetic, to make noise, to have fun. This activity made people relax, calm down and contemplate the transfomation of a cool grey gaping space they couldn't possibly lie down in, into something warmer and more embracing, I remember falling asleep there more than once.
http://www.lozano-hemmer.com/video/subpub.html
http://www.tate.org.uk/modern/exhibitions/commonwealth/