I don't think there's an issue. I've never noticed anyone having them taken off them and we even have our own massive flag that comes out for big games
Hi treenie, its a bit of a tounge in cheek question as our owners stopped us taking in or putting any sort of flag up that said "SISU OUT". We had a lot of problems with this and one day even had a mini riot in the ground. The club stance was that all flags and banners must have fire certificates. they do not like bad publicity.