There are quite a few BYO's in my area (NJ) so I usually keep two 2-packs of Riedel O's in my trunk. Not my first choice for stemware, but often 100 times better than the $.25 glasses at some of these places.
I am a regular at some of these places and when coming in with a larger group (6-10) I usually have multiple decanters (small Riedel Vivants from Target) along with my 8 pack of knock-off O's. At one place the wait staff always rinses them for us and we tip accordingly. This is an improvement over the full sized decanters and Spiegelau stems we used to walk in with!