Makeup artist for my sister's wedding wants full payment upfront, no contract — normal or run?

Helping my sister organise her wedding beauty stuff (she's drowning in other planning). Found a MUA on instagram whose work is genuinely stunning, exactly the soft glam vibe my sister wants. Portfolio full of brides, tons of followers, replies quickly.

Here's where I've gone a bit hmm. She wants the FULL amount paid upfront to secure the date (it's 5 people total so we're talking a few hundred quid), there's no contract or even a proper booking form, just bank details in a DM. When I asked about a trial she said trials are extra and bookable "if there's availability" which feels backwards?? Surely the trial comes before you commit to the full wedding party?

Every other vendor my sister has booked (photographer, venue, florist) did deposit + contract + balance later. Is beauty just different or is this MUA winging it business-wise even if she's talented?

For anyone who's booked wedding makeup recently — what's the normal payment structure? Deposit percentage? And is asking for a proper written agreement going to make me look like a nightmare client before we've even started?