When going to the invitations tab, I think it should be physically harder to accidentally click on reject invitation. This doesn't have to be radical, it could just make them double-spaced. It would probably be easiest with an actual Horizontal line between them so that people have a reference frame. I don't have stats to back this up, but I am pretty sure most invitations are accepted, so the decline could be made smaller.
Concise description:- the decline invitation button will be moved farther away from the accept invitation button
- perhaps it will also be made smaller
How this will benefit the site and/or other comments:- those of us who play on phones or other small devices won't misclick so much
- in general, invitations will be accidentally denied less