I have been wondering for a while if it was normal that my ET4's fender was so... er, Floppy. I had some time to have a look this evening. You know the three (3) mounting bolts holding the fender to the steel plate of the steering tube? Mine had One. Count 'em!!
The "Correct" way to fix this involves dropping the fork, which entails dismantling the entire scooter, plus several other scooters nearby. Nope, Not Gonna Do it!
Closer inspection revealed that there actually is a little room to drop a bolt down from the top on the left side of the triangle.
Step 1: Find a perfect-length bolt from Junk Drawer. Fortunately I have extensive Junk.
Step B: Find a nut that has the correct thread size and thread pitch to fit the bolt from Step 1. Eventually the score was made. Plus a fender washer and lockwasher. Not too hard to thread in and tighten.
I could have stood pat at this point. The access to the Front mounting point is WAAAYY too small to insert a finger, much less a 3/4" bolt. What to Do?
Step 3: Select another bolt of the PERFECT Length to show a few threads above the fender.
Step 4: Using a curved hemostat from my Medical Kit, I was able to hold a nut over the hole from which the bolt inserted from below - see pics - just enough to engage the threads and tighten the bolt from below. Once the nut - no way I could add a fender washer - engaged the plastic fender, it dug in and didn't need to be held fast to get tension enough to compress the lock washer under the bolt head.
Fender now is firmly affixed, and Little Victories like this make Vespa life a pleasure.

Up-and-Down Floppiness seemed excessive...

2 out of 3 ain't bad, but 1 out of 3 was just not Acceptable. Easy to get to the left one from outside, not so much the front one.

Space too skinny to get a bolt in from the top without trained Spider Monkey...

Curved Hemostat to the Rescue!! Working in the dark with a useless headlamp, mostly by feel, the bolt threaded in...