That reminds me of a service call I got on xmas eve, to a freeview box not responding to the remote. When I got there it was working perfectly.
At 4pm when I thought I had finished for the day and was having a cup of tea,the call centre phoned me.
"Any chance you can go back as the remote has stopped working again"
Now it's a 30 mile round trip to this customer but I said "Yes".
When I got there I spotted she had put a small santa clause ornament directly in front of the IR receiver of the stb. On the previous visit she had cleared the ornaments away.
I was not a happy bunny.