I'm Scottish too and have always shown my own houses. I hate it on the rare occasion an EA shows a house - they never know the answers to all my questions.
When selling my last house viewers did all sorts of weird stuff after I'd left them alone to have a look round.
One person went through my (freestanding) wardrobe and drawers.
One couple lay on the bed.
One couple broke something (and didn't mention it).
One couple removed all the cushions from the beds and window seats in every bedroom and put them on the floor. 
One woman fed her toddler chocolate and I just caught his smeary little hands just before they hit the hall wallpaper. She said "isn't he adorable?"
I said "would you like a baby wipe?"
One couple let their children play on the garden playset (without asking) after their viewing (which I didn't mind) but they stayed so long that they were still there when the next viewers arrived and the DH was furious. He accused me of deliberately staging things so they'd see each other.
He was even more annoyed when I pointed out that he was my 4th viewer that day and that I had another 4 to go. In order to fit everyone in they each got a 40 min slot. That rather took the wind out of his sails.
My favourites were the terribly naice older couple who had a massive, really loud sweary row upstairs for 15 minutes and then walked downstairs holding hands and chatting away as if nothing had happened.
And then there was the woman who hopped up on the kitchen counter while chatting to me.
Seriously- who'd want to let the EA have all the fun and miss out on the drama. 