Not sure what this might mean, but there was green tape on some of colossus' supports today that looked relatively new. They're along the queue line next to the walking dead building. I don't think it was painters tape either as it got done not long ago. This is probably nothing but thought someone might have a clue as to what it could be, if anything. I'm still a bit new to make a judgement really.
Is the tape on the ride supports of the lift hill, or on the track going into the station? I don't suppose you got a photo of it?
I've been taking a closer look at Colossus since it had a week long closure earlier this year and haven't spotted anything that looks out of place yet. My last trip was a few weeks ago.
The simplest thing could be that they're using it to mark out where they want lighting for Fright Nights, although I'm sure the lighting was left up from last year. But strange markings appearing in places may have more interesting meanings!