No, because you have to have an INTENTION to get married.
As an example I could show a room of students how to draw up a will, I could then go through the act of executing said will, however with the INTENTION to create a will the act is just that, an act.
Most TV and films these days seem to be in 5 second (10 if you are lucky)soundbites and I doubt if they are shot in order. So until they are editted together there isn't a coherent wedding to be legal.
As advised, ther person conducting the 'marriage' has to be legally sanctioned to do so, and the place has to be legally sanctioned for marriage purposes, and the people involved have to have applied for a marriage licence in their own names.
Any one of those three makes a TVr theatre 'marriage' invalid - most include all of them.
Last night I was reminicing (sp) about how when I was a kid I always thought the reason they never showed the whole wedding on a tv show was because it would mean the people were actually married in real actual life. Not just because it's utterly dull.