You may see that this workflow has a lot of advantages. It is a sort of "virtual" editing where all the edits are in separate layer (the keyframes in Multi-Cam plugin)
Some Tips and Tricks
Pre-Sync
Before you start filming, you have to think about syncing the footage. If you had previously done any multi-camera editing, you know that with all the amount of footage from multiple cameras and all the wedding scenes that tends to blend into utter chaos the very next morning, it is a very tiresome experience for somebody sitting behind editing station at two o'clock in the night to guess the sync without some sort of visible and obvious clue. This should be one important thing to remember before you even start.
A professional crew uses "Jam Syncing", which is not as the name suggest smearing marmalade on the bride but rather plugging all cameras into a timecode generator.
This is often not an option for a normal videomaker (altrough you may try to suggest the marmalade part which could work very well in our opinion). However a favorite method of Hollywood, the clapboard, usually is. A somebody who usually pretend to be Hollywood film-maker to impress the girls would call it "sticks".
You don't actually need sticks (here, here), just enlist some of your bored crew member, or a lonely bridesmaid to stand where all cameras can see her. Start the cameras rolling and let the person to visibly clap or jump or do something equally enjoyable (or humiliating if it is your sleepy crew memeber). Alternatively if all your crew members, bridesmaids and friends deserted you or it is not appropriate for a sane person to jump and clap in front of a president, hungry lion pride or both, just quietly start all cameras, dust off your digital photo cam with working flash and take a good nice picture of the scene (with the flash of course!). Just make sure nobody else get the same idea at that particular time. Or feed the lions...either one will make a good, memorable sync point.
Once rolling, keep on going
After you sync the cameras (by any of the combination of jumping, clapping, flashing(?), feeding the lions or bridesmaids) do not stop or pause, just keep rolling.
Pausing the camera is a sure way to make the editor person to hate you, because he will need to re-sync the footage, if he actually spot the unexpected pause at all in the loneliness of the wee hours.
If you need to pause for any longer time (filming in a bathroom may be viewed as distasteful even if you try to explain the awkward syncing issues), stop all your cameras and then try to later sync them as before.
If you still need to re-sync the cameras in editing (for example tape change, or slippery fingers on the pause button) look for obvious clues such as eye blink of a person, photo flash or groom sneaking away (the latest may not be always readily available).
Use the same model of the camera
Or at least similar models. Different models will produce differently looking picture and white balance which will need to be adjusted... or pretend the issue doesn't exist and call everybody else colorblind and your footage marvelous.
Audio
It is common that one camera will be set as the main audio source and used as a primary sound source because you want to have the audio constant, not change with the camera cuts. Eventually you may simply bring up sound from different camera as needed (somebody speaks close to Camera 2 etc..). You usually want to use external microphones for the main audio Camera as it will be much easier to control the sound.
You may try to also use external audio recorder for the whole audio to obtain better quality, but it may be problematic or impossible to synchronize this one with the video if you don't use timecode generator. (Jam, remeber?). Recorder without time synchronization with video may get progressively out of sync with time.
Do not try to top MTV
Wedding should not be cut like a rap video (unless it is a rap wedding). You have to remember who will be viewing your edit and that often includes minors or folks over 90. Do not try to trigger seizure in them with machine-gun series of fast cuts. Edit peacefully with the music... your job is not fast forward through the whole footage in five minutes, the viewers can do it by themselves.
You can use multi-cam even for small family celebration
This doesn't mean the family has to feel like they are filming an episode of Mexican soap opera. You don't have to enlist your uncle and grandma as your film crew. And you definitely don't have to call your neighbors to make the laugh track.
You can put small cameras on tripods strategically placed in a few corners, switch them on and leave them alone. Then perhaps use just one camera as you would normally do to film any family event by caring it around. But this time you will have much more footage to fill up your hard disk from all the secret eyes in corners... and so you can see who was secretly munching on the cake or who drank all the vine when you were looking away. This will sure made the final cut from your event much more popular.
