Turning up as a surprise is awful for everyone except the one whose idea it was. Utterly selfish (…”I know what’s happening, tee-hee, and THEY don’t…, the kind of glee a certain type of person takes delight in.
When my ex’s stepfather was dying, my BIL decided he’d arrive unannounced from Australia, to delight his mother, and kept saying he just couldn’t wait to see her face when she opened the door.
I said, “She’s going through hell nursing her husband. Give her something to look forward to. Tell her when you’re coming, and for how long. Let her revel in planning your stay, let her enjoy telling her friends and family. Rather than giving her two weeks of happiness, give her also the six weeks or so of pleasure before you arrive, instead of keeping the thrill of your secret to yourself (and expecting us to). Her face when she opens the door to you will still be pure joy, delight and love, but the thrill of shocking her would be yours, and yours alone. Share the delight instead of keeping it to yourself, and denying her those weeks of excited anticipation”.
My ex took some persuading too, but they did agree to tell MIL instead of surprising her, and what joy it gave her.
Surprises may be delicious for those planning the surprise, but terribly selfish and unfair on those kept in the dark.
They’ll have planned food etc, you can’t just turn up on Christmas and assume they’re able to cater for and accommodate unexpected visitors. I’d be beyond livid. Plan a visit on an agreed date.