My Dad's dementia has deteriorated to such an extent that odd comments are no longer a problem. However starting about 3 years ago, until maybe 1 year ago there were situations where i was beyond embarrassement. Helping himself to stuff in shops then walking out and going into meltdown if challenged by security, paying with monopoly money (yes really) eating off other people's plates in cafes (that's off other customers, not my or his carer's plate), attacking me with a fork in a cafe when I asked him not to pinch someone else's food, sitting in Boots shouting "**** **** **** " repeatedly because we were not served instantly (and may others). My way of coping was 1) telling myself I was dealing with enough and if others were a little put out then so be it, I wasn't going to stress about it 2) wherever possible in a public place such as a pub/ cafe/ shop tell someone in charge what the situation is, warn them Dad might act odd it's because he has dementia and i will deal with it. The later approach nearly always drew a helpful response from people. As someone higher up said, people are often fairly tolerant of elderly people acting odd, and there's a good reason for it!