probably
allegedly is a weasel word which is used as an excuse to say something which is quite likely true.
probably is a weasel word which is used as an excuse to say something which is quite likely not true.
whenever i see probably on a sign i feel they should add what the probability actually is.
in this case it's probably (less than 1% chance) that the best music in the world will be played there. unless they are talking about genres then it might be nearer 40%
It's like the word "almost." Many times it is used in places that doesn't fit. "Look! That woman is almost pregant."
"Very" is the same way. "She is very pregnant."
I'm almost always amazed at how very allegedly possibilities present themselves. Yack!