I actually have the gold number saved to my contacts from the good old days when I actually was gold. Definitely called since I dropped to silver and was not told off. That said, it would have been to deal with May bank holiday issues so perhaps BA were being more flexible then...

In any case, it must be pretty common for people to save this number and then change tiers... not like I had it saved as 'BA Gold Line' or anything DYKWIA like that