Why would a contractor leave temp barriers up for three months?

Three months is defintely long. In fifteen years of doing small masonry and brickwork jobs, the barriers came down the same day we packed up the tools, or at absolute worst the next morning once the mortar had cured and we'd swept the site. There's no inspection rule that requires barriers to stay up after repointing. A sign-off might hold up a final payment, but it doesn't mean the footpath stays blocked while everyone waits on paperwork.

Funny timing, I had nearly the same thing on my street last year. Barriers sat there through winter until someone noticed weeds growing out of the sandbags holding them down. Turns out the contractor had finished and the property owner was supposed to deal with it, so it just sat in limbo for ages.

If it's on a public walkway, I'd snap a pic and send the town a quick email, not a complaint call. Phrase it as 'hey, is this still an active job?' That way you're not pointing fingers, you're just asking. They've got records of permits and can chase whoever's responsible. Zero awkwardness with the neighbors that way.

The limbo thing is real. On a fence job I did a few years back, our panels sat outside a shop for six weeks after we were done because the council permit had an expiry date and nobody wanted to pull them early in case the inspector drove by. Wasn't laziness, just paperwork fear. Worth asking the crew or the town wheather there's an open permit on the job, because if there is, that's your answer. If not, the email route will sort it inside a week ussually.

We once left two panels behind a job for a couple weeks, purely because nobody told the laborer who set them up that we'd wrapped. Client called the number on the little contact sticker we clip to the frame and it got sorted by lunch. Those stickers are just laminated card on a zip tie but they've saved us loads of awkward shipments home. Might be worth checking if the panels on your stretch have a firm name or number on them anywhere. A friendly call goes further than the town office, and the crew can usually send someone with a van in an afternoon.

Update: sorted. Went back and checked the frames properly and there actually was a little contact sticker zip-tied to one of them, half faded. Called the number, bloke said the crew had wrapped weeks ago and nobody told the laborer who set them up. Panels gone by the next afternoon. Felt a bit daft for waiting three months to do that.