Well I don’t know if it’s the “exotic factor” of being an Italian trying to speak Welsh - that people don’t really seem to expect - but I have to say that all Welsh speakers I met were really nice and lovely! 
Since my vocabulary is very limited, I often sneak in English words in the sentence or ask them for the word in Welsh because I don’t know it and…people just answer.
Yes, sometimes people do switch to English - or even Italian and Spanish. But sometimes I switch to English too when I’m confused and lost - and I think it’s normal in real life/everyday communication, doing everything possible to understand each other.
[edit] I just read the first post, so I have to add: in my experience people are more likely not to speak Welsh in my presence, so to make sure I understand, not the other way round!