Past tense

I took a load of my gran's old clothes & old suitcases & things to charity shop this morning. Had to empty the loft for it to be insulated.
I told lady in shop they were all my grandmother's things - just to tell her they were lady's clothes rather than anything else. Shop lady said of the suitcases,"she must have been quite the traveller" seemingly thinking that I was talking about my grandmother in the past tense as she was dead. I was using past tense as the clothes & things were old.
I suppose it's an honest mistake to make but also I think I tend to talk about people in the past tense inappropriately too. I'm often telling people my father was Scottish; I assume he still is.