Laura Whitford decorated the centre of Royston with colourful nets and bunting to publicise a craft fair on Saturday.
The nets have been thrown on to a roof and into trees almost every day since she put them up on Sunday night.
However, Mrs Whitford put her story online and said so many people saw it, everyone "now knows about the fair".
She and her friend Anne Walls crocheted covers for bollards in the centre of town and a large net to cover the Royse Stone - a landmark that used to contain a cross, and which gives the town its name.
They put them up, together with crocheted bunting "under cover of darkness, like all good guerrilla knitters and yarn bombers do", she said.
However, on Monday morning they were gone. Mrs Whitford posted "missing" notices on local Facebook group pages. The items mysteriously reappeared that afternoon.
On Tuesday, the nets were discovered strewn on the pavement and thrown into trees. They were retrieved and returned to their rightful positions.
The following day the stone cover was spotted on the roof of a bank.
Staff from a nearby pub brought out a stepladder and retrieved the cover for Mrs Whitford.
However, it has happened again, she said.
"They're back in the trees, but frankly that's where they're going to stay until the fair."
Mrs Whitford added: "Actually, I'd like to thank the vandals because they really have done me a huge favour, and this whole saga of missing netting has given the fair more publicity than I ever could."
A yarn bomber says vandals who repeatedly removed her woollen artwork, throwing it around a Hertfordshire town, have done her "a big favour".