Quoted by GG.
I think it is OK for them to wonder, and also that they almost per definition expect the kilt wearer to be a non Scot, but if they, as you say, take ownership of the kilt, shouldn't we foreigneres fear a hostile reaction from them, too, when wearing what they feel are their "property"?
After all tourists normally expect to be well received when visiting a foreign country and not be met with suspicion and contempt.

A lot of germans wear a kilt when on holiday in the highlands and I have spoken to a few. They usually are well received in tourist area's and have not had any problems. As far as the lowlands are concerned, Edinburgh, Stirling etc. no problem but leave ya kilt off in Glasgow unless it is a special occasion or a football match.
Most locals, I have found know their own tartan and perhaps a few others but show them a random tartan and they would not know what clan it is. I know most by first name only so the question of clan is something I have never encountered. There are a few clan meets up here, Sinclair's, Gunn's are the main one's so I would not turn up in another tartan (I was invited by John Sinclair (Lord Thurso) once (I used to look after his computers) But was not able to go.
I don't think foreigneres should fear a hostile reaction unless your wearing this...
http://www.englishkilt.co.uk/gallery...ry/image14.jpg
Oh dear I have no words!