My nephew is getting married next weekend. They have hired a professional photographer whose contract is pretty explicit about not allowing other photographers to shoot....which I understand completely and respect!

That being said, I plan to bring a camera to take more candid, unposed and random photos. I do not want to interfere with professional photographers, but can’t resist bringing a camera...

What suggestions do you have for me to stay out of their way, but still get some great shots to share with family/friends?

I was a pro photographer through my entire adult life doing weddings, bar & bat mitzvahs, 50th's, etc. Everyone I worked for had the "exclusive" in their contract incl me, when I went on my own. I shot my last paying job in 8/2009. Back in the 1970's we worked almost exclusively with multiple lights. A "light-man" (kind of a human light stand who carried the off camera light to open bachgrounds, give a more 'main-key light to the camera light as the fill for a more portraity effect on formals, various groupings [one or more YOU might be in being an uncle.] Theoretically he's also learning what the photog'r does, how it's done, & how to handle all the various personality types esp when they're at their most nervous & excited point of their lives...a photog'r if he's good is sometimes more psychologist than picture taker. That second light used a white light flash slave. If someone was shooting our posed shots we often worked our way behind the subjects & pointed 200 w/s towards the offender & if he had an SLR & closed his other eye, he'd never know that his pic was ruined till next week after devlpmnt. Generally think this way, besides his making a living at it...yeah sales are great...think of what happens when people are set up & there's 2 or more cameras. If it's the bride & groom one or both, in confusion might be looking back & forth between the cams, in essence a ruined picture & you can imagine if it's a group shot of 4, 7, 14, etc.
Usually, if you weren't interfering with what I "NEEDED" TO GET, I didn't much mind, within reason (ie: you'd get shots of your own friends &/or family, people at your table, etc. Just stay away from him even at the reception...the 2 cams problem again...even on a dance floor. I actually agree with the guy who said to call the studio...or approach him at a time he's not busy & ask him...tell him what you'd like to get & if you stick to plan, would that be OK. Also tell him his pix are #1 & if he quietly says "cool it" you'll put it away. A cam slung over your shoulder will not get the sunjects darting their eyes, not sure which will shoot 1st. There's much more but I have to stop. 1 more thing though...you can also ask him if he can, during an off (slow) moment at recptn take a couple or more pix of YOUR family (wife, kids, grandkids, etc.) Who knows...you might get a few nice shots (& have to pay for them too), & it 'could' look like you went to a family affair &
had a nice time....MAYBE EVEN DANCED! When we had a celebration for one of my kids, my pro friend started to ask me if I wanted to....I cut him off & said, "Just put me where you want me, call your expressions, get the shots you know you need...then leave me the "F" alone! I had the time of my life...& it CAN be done without having a camera within your reach. Sometimes your feeling like preserving great memories makes them not so great for YOU. You're thinking of what to get & how to get it makes you miss some of the most beautiful of what happens...what is said about grandma in the old days, a funny comment from a 5 year old grand niece & her wedding plans...well...you get it...I hope.