I sneak mine into the laundromat also.
I've been known to drive by a few times a day, and when I don't see a lot of people I dash. I bundle the blankets up in hopes that people assume they are sleeping bags... or something... not horse blankets ;)
Toss 2 sheets or 1 blanket per front loader, cold/cold. Come back 1/2 an hour later or so right before the timer's up, and get soaking wringing wet sprinting to and from the building to the car. By this time I think people know what I'm up to!
When I back out of my parking space and they see the horse decals on the back of my SUV they probably cuss me out as I drive away.
Haven't washed mine this year yet, there may be a "DO NOT let this girl in our laundromat!" sign.