@Bonjourfreddie i personally would be fine with it, its clear the ops intentions were good and i would prefer to see the dress, the venue, the heartfelt vows etc than them signing the register. All those things are what make a wedding, and ok it wouldn't be a legal wedding but it would be a lovely day and that would be the day i would want to be involved in.
Oh, and we ONLY did the legal bit - which you keep saying is just 'signing the register' - it's not, you also SAY YOUR VOWS.
We did not bother with any of the nonsense like dresses, rings, venues, all that bullshit.
Our parents all still thought it was worth making the effort to come out on a rainy weekday morning in January (in the case of my in-laws, travelling about 300 miles just for this reason) to see us 'just' signing the register and saying our vows.
Because funnily enough, as two married couples who have each been married for over 40 years, both my parents and my in-laws recognised that actually, the dress and the venue is all meaningless bollocks.
Their collective experience of decades of marriage meant that they understood that what was important was to see us ACTUALLY marry each other.