A very welcome visitor from next door

My next door neighbour has the most amazing rose in her garden, and by some miracle of luck, it has grown over to our side. 
I think it started last year when we notice it had climbed up a tree on our side.  This year it kind of collapsed onto our side, and the spur grew so much that I swear we are getting more benefit than they are. 

What do I do?  It seems an absolute travesty to cut it off, but I have a sneaking guilty feeling that we should be offering it back?

There is a saying that you should offer back anything that you take off the plant, so I guess that means if we pick any.

The whole thing makes me feel somewhat like a character out of the fairy tale Rapunzel.