A standard practice of wedding planners is to carry an 'emergency kit' - to deal with all sorts of issues that could come up at a wedding. I know you all remember Jo Lo's special jacket in the movie The Wedding Planner.
So what is an Emergency Kit??
There are many different types but I know they are all bigger and more involved then a 'special jacket'. Mine is a small suitcase that I can throw over my shoulder. Some things that I can't live without:
stain remover - yes I can get red wine out of the gown
Big saftey pins - yes all bustles come loose
tape-clear, masking, duct, floral
cd of standard wedding songs
I also keep spare unity candles, cake knife, ring bearer pillows, black socks, hand held sewing machine, umbrellas and a bottle opener handy.
Some weddings I end up using many items from my kit and I am so thankful I had it to save the day; Better to be safe then sorry.