I live in the Netherlands, where it's not the Americans assuming everyone speaks English. Sometimes it's quite bizarre too: we have this deaf, Ukrainian colleague who doesn't speak but communicates with Russian Sign Language (and whatever gestures you can think up on the spot), and it's very blatant that he doesn't speak English because he doesn't speak and can't hear, and has never written any notes in English or anything like that, but I've still caught other colleagues mouthing, or sometimes outright saying, things to him in English, as if it'd help. I remember once coming across a mute man who obviously understood Dutch, who then tried to ask someone a question, who then replied in a very "my husband is antiquair" kind of way. Otherwise it's mostly European tourists and immigrants who assume you speak English.
I'm a native speaker of German and of course I spoke English to the people in the Netherlands when I was there. I don't know any Dutch and don't expect them to speak German, so English is pragmatically the language that we have most likely in common.
We're talking about the assumption rather than whether it's more likely. German in the Netherlands is a poor example, as it happens, as a lot of Dutch people speak it to some extent, but now you mention it, Dutch people often complain of Germans assuming they understand German.