I'm not quite sure why you are imputing the claim that "EVERYTHING is art" to me - I don't believe that and never implied it!
I know defining art is an age-old debate, so I'm not going to get into that. However, if I experience a work of art and I'm still thinking about it the next day, or week or year, then I feel the art has some effectiveness.
If I experienced the gaffer tape and the next day I am walking around watching people behave with a heightened perception of boundaries around individuals and groups, then I would feel that the artist has achieved something (of course, that something may be transforming me into a pretentious idiot
). If my only thought is "oh, that reminds me, we're out of parcel tape - I must pop to Smiths", then the art has failed. 