wouldn't really matter, they'd just stop filming. it's been done before, i think. not the whole "rights change during filming" thing but the "drop everything for this production," especially considering the movie is a good 2 years off.
[url=http://moviepilot.com/posts/2014/05/13/is-marvel-getting-spider-man-back-should-they-1422292]source[/url]
Thanks for the source, I couldn't find anything. It will be interesting to see if they do and what they do with it. I wish it happened sooner as I woulda preferred Spidey over Hawk eye in the avengers.