I haven't complained about the Cataloonies for a while, so here goes. To my knowledge, in Catalonia, right now, it is legal to label your product either in Spanish, in Catalan, or both. This, right here, is dangerous, because the problem is that EVERYONE in Catalonia can read Spanish, including all of the many visitors from other parts of Spain and quite a few of the visitors from foreign countries, but my guess is that one-quarter of locals and 99% of visitors from other parts of Spain and foreign countries can't read Catalan.
Now, most of the time Catalan and Spanish are quite similar, but occasionally there might be a major problem. Take, for example, my mom (in real life). She's both diabetic and allergic to gluten. Let's imagine my mom is a working-class immigrant from Andalusia who's been here in Barcelona for 25 years but isn't well-educated and can barely read Spanish, much less Catalan. Fair enough? There are quite a few people like that. Now, my mom can figure out that "trigo" means "wheat" and that "azúcar" means sugar, and she knows enough to read the labels on food products to check if they contain those things. But will she be able to figure out that "blat", not "trigo", is Catalan for wheat, and that "sucre", not "azúcar", is Catalan for sugar? This is why all product labels should be in Spanish because EVERYONE understands it. If companies want to label in Catalan as well, that's just fine, but they should be required to label in Spanish.
Another example is highway signs. Now, most of the time Spanish and Catalan are pretty much the same. "Centre Ciutat" is pretty much the same as "Centro Ciudad". But all highway signs should be in Spanish because it's the language everybody can read, including all drivers from other parts of Spain and many from foreign countries; for example, every trucker who covers the Alicante-Copenhagen route, knows how to read Spanish, no matter if he's Danish or German or French. But would a guy from Cuenca driving to Gerona, or a working-class van driver from El Prat, know how to figure out this temporary sign that was up for a couple of years in the very early '90s while they were working on the N-II, the main Barcelona-Zaragoza-Madrid highway: "Perill. Pont tancat." Which, in Spanish, would be "Peligro. Puente cerrado." or in English, "Danger. Bridge closed."?
Again, if the Catalan government wants to require the use of Catalan on road signs in Catalonia, that seems fair enough, but it makes absolutely no sense not to put them up in Spanish as well.