I had quite a few issues using the North+Mid Wales rover on buses last summer with drivers who didn't have a clue what the ticket was (as the words 'Rail Rover' are very helpfully printed on it...
All but one drivers were more than happy to accept it when shown the T&Cs from the ATW website. One driver even asked me where I'd been on the train with it as it looked like a really good ticket! (As did a Virgin RPI at Crewe for that matter)
I had no issue using the ticket on the morning WAG to Shrewsbury either, nor on the 08:35 Chester-Euston as far as Crewe.
I ended the week by travelling on the Mold-Ellesmere Port route operated by Stagecoach. The driver initially point blank refused to accept the ticket, and wouldn't accept the T&Cs as 'we don't accept Arriva tickets'. (That route was *specifically* mentioned as being valid!) He soon realised I wasn't going anywhere and reluctantly let me on.
Upon arrival, he told me that Arriva had ran that route (apparently on a short term measure when GHA Coaches went bust) so suspected that the website may have been updated around that time. He also said he was going to look into it as he was fairly certain that the ticket wasn't intended to be valid on Stagecoach-which, to be honest, beyond the Welsh border and into Ellesmere Port, I'd be inclined to agree with.
The quite lengthy detail of what buses were valid disappeared about 2 weeks later. So I wonder if Stagecoach have made a complaint and they've realised it was out of date and panicked...