FI and I had originally decided against favors because we thought it'd be a waste of money, but after getting caught in an unexpected downpour last week (yay autumn), I started tossing around the idea of ordering umbrellas as a favor.
A little background: It's a daytime wedding, early January in Washington, so it'll be chilly but not freezing, with a 80% chance of rain or sprinkles coupled with a 100% chance of gray skies. Nothing immediately related to the wedding will require having to stand outside, but the venue is on the waterfront, and the coastline is pretty enough even in winter to invite a stroll. A good chunk of the guest list is coming from out of state and probably wouldn't be prepared for inclement weather.
I was thinking of ordering enough for like... half(?) of the guests, and piling them in a basket near the door, like some weddings have shawls or flip flops. Guests could take an umbrella and go sightseeing/start a sword fight/have a Seattle-ish favor, or they could leave 'em according to personal preference. I'd be okay with a lot of extras because I lose them easily and like to have a stash (I'm convinced they end up in the same place that socks disappear to). Oh, and no, they wouldn't be personalized.
If you were a guest, would you think WTF? Am I way overthinking this or could this be useful?
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Re: Umbrellas as a favor?
If I were out of town I would either run to Target and buy myself a cheap umbrella or I would just deal with it. It seems like it could be difficult to bring back on a plane with you if your suitcase is full.
Like manateehugger said, I also wouldn't assume I could bring them home with me.