And despite the fact that hundreds of thousands are expected to crowd Windsor on Friday to witness the royal event, a petition has even circulated in recent weeks to prevent taxpayers having to pick up the estimated $5 million security bill.
"Who's heard of Princess Eugenie anyway?" British parliamentarian Chris Williamson said in an interview with Sky News. "She carries out no royal functions, no useful purpose to the public sphere and yet we're having to spend this kind of money."
Ouch.
Even Eugenie, 28, admitted earlier this year that it can be tough in the unique limbo she and her sister live in as "minor royals". They're close to the throne (Beatrice is eighth in line, Eugenie ninth) — but not close enough for a full-time job with the Queen.
"There is no precedent, there is no protocol," she told Vogue. "We are the first: we are young women trying to build careers and have personal lives, and we're also princesses and doing all of this in the public eye."
Here's what life's really like for the second-tier royals.
ROYAL PROTECTION
While Prince William and Prince Harry are each afforded an elite Scotland Yard squad to guard them, their cousins — the children of Prince Andrew and Sarah Ferguson — were actually stripped of their 24-hour police protection in 2011 amid public outcry over the $101,0000 annual cost.
It infuriated the Duke of York, who was then forced to rehire his daughters' bodyguards out of his own pocket.
NON-WORKING ROYALS
Without a piece of the Sovereign Grant (that is, the annual cut of profits from the Crown Estate that bankrolls the Royal Household) Eugenie and her sister Beatrice, 30, have been forced to live their lives in the public eye … but with actual jobs.
Perhaps sensing the awkward position this put them in, their father put up quite a fight to have his daughters included in the Sovereign Grant.
The duke wanted Beatrice and Eugenie to become "full-time" royals like their cousins, which comes with a list of official duties and separate flats in Kensington Palace, but his pleas to the Queen were rejected.
It's understood Prince Charles — who is heir to the throne — was very supportive of his mother's decision, as he was keen to create a more streamlined monarchy.
But just because they're not included on the royal meal ticket, Eugenie and Beatrice haven't exactly been slumming it.
The pair shared an apartment within St James's Palace until April this year, at which point Eugenie and her soon-to-be husband moved into Ivy Cottage (next door to Meghan and Harry's place) at Kensington Palace.
Eugenie works as an associate director for the Hauser & Wirth art gallery in London, while Beatrice has a job at US technology firm Afiniti.
By comparison, their aunt Princess Anne probably did her daughter Zara Tindall (nee Phillips) a favour when she refused the Queen's offer to give her a "princess" title like Eugenie and Beatrice.
The professional equestrian and mum-of-two has managed to stay relatively low-profile while maintaining strong ties to her royal family. Zara's carved out a career worth millions through endorsements and business deals and dodged most of the intense public scrutiny applied to her titled cousins.
And while Eugenie and Beatrice may not receive any money from the taxpayer, their glittery lives have certainly raised some eyebrows over the years. According to iNews, between November 2014 and December 2016, the princesses took approximately 25 foreign trips between them.
They've also got a very glitzy inner circle, made up of celebrities including David and Victoria Beckham, Ed Sheeran (who could forget Beatrice slicing his face with a sword at a party in 2016?!), Robbie Williams, Mila Kunis and Ashton Kutcher, Ellie Goulding, George and Amal Clooney, supermodels Karlie Kloss and Kate Moss, and actor Eddie Redmayne.
Not a bad life.
SOCIAL MEDIA
She may get a raw deal in the royal stakes, but there's one thing Princess Eugenie has over her higher-profile cousins: an Instagram account.
Even Harry's wife Meghan Markle was forced to shut down her social media accounts once they became engaged, but apparently no such protocol surrounds the York sisters.
Eugenie runs her own personal account (@princesseugenie, in case you're interested), filled with personal photos of herself and her family, along with some snapshots of her working life.
Meanwhile, Beatrice's private account was accidentally revealed in July by her famous pal Karlie Kloss in an Instagram story.
The Victoria's Secret model was posting various reactions to her engagement to Joshua Kushner from her friends — one of which was Beatrice, under the handle @beayork.
The private account still exists, but is inaccessible to those outside her inner circle — currently, she has approved just 658 followers.
