It doesn't matter whether you try to make money out of it or not, it's whether their legal team can make a convincing case saying that you've cost them money.
That's got bugger all to do with it. Loss and damage are vast concepts in law so it doesn't have to be purely monetary.
A lot of people on youtube do covers one of the better ones is Walk Off The Earth who cover a lot of more recent and popular songs and they seem to get away with it, infact i think they sell them on itunes so much have sorted copyrights out but im not sure.
