Honestly, there isn't a difference (in my humble opinion) between a FWB and random hook ups on Tinder! The bottom line is honesty, really. Say what you're really looking for and don't lead folks on and it's all good.
The problem, at least in the States is, people tend to think no one else is looking to just hook up. So, they pretend they're interested in something more. No one really wins in those situations.