I would really like you to Trademark DFTBA and Don't forget to be awesome, mainly because this is not the first time that urban outfitters has ripped someone off, and mainly they seem to rip off small creative artists on Etsy, and take their designs, send them to a Bangladeshi sweatshop, and have housewives pound out thousands of copies for pennies a day. In short, Urban Outfitters are kinda douche-y. Now to rebut your points specifically. 1. The "defend it or lose it" argument, is, kinda bullshit. Go here: http://redkiteprayer.com/2013/12/the-explainer-because-i-ing-hate-bullies/
to have an actual lawyer explain why. And, the other aspect, the DFTBA scarves, the trademark system actually has a built-in mechanism for this, which is, you can license uses you approve of, so if Urban Outfitters decides to make sweatshop-labor DFTBA towels, you can sue the pants off of them. If somebody decides to make an awesome DFTBA scarf, you can say. "That is awesome, here is your license to use DFTBA to make these awesome scarves" I'm all about solutions. And destroying Urban Outfitters.