I'm good friends with the two people getting married, I'm just not in the wedding party. My best friend who is in the wedding party was actually the one who suggested/asked that I take my camera and try and get a few good ones because he doesn't know if the couple getting married has even hired a photographer and if they did, if that person is any decent because the groom is "cheap" with certain things. For all we know, it could be "Aunt Jane Smith" with a point and shoot doing the wedding. My main reason for even bringing my equipment was "just in case" because nobody even knows if there is even a photographer and if that person even has a good camera/experience.
In terms of an isle shot, the scenario from what I have heard is that there are 180 confirmed guests , but only 50 chairs. This means that there's going to be a lot of people standing and crowded around. I never planned on actually standing in the isle to take a picture. I was thinking more along the lines of an isle seat or standing somewhere at the back and trying to get a couple shots of them walking. And then I was thinking about using the 55-250mm to get a few shots from my seat or from the standing room in the crowd.
I've been around photography my entire life, I'm not stupid enough to ruin someones wedding shots by jumping in front of a wedding photographer, if there even is one there. I'd be fine with just taking my point and shoot and enjoying the wedding.