Both parents are planning surprises for each other for their anniversary, and talking to me about it!

Hi!

I've been a lurker on this subreddit for a while, but this is my first post; it feels like the right topic to post about for advice! I'm a nanny for two twin boys, and I absolutely love my job.

So, the parents have their wedding anniversary coming up. I texted the father a month or so ago about coordinating a surprise for his wife. He has plans to take her out to dinner, and he's contacted two of her friends who she hasn't seen in a while to join them (that's the big surprise element!). Today I received a private text from his wife, asking if I'm free on the same day to watch the boys so she could surprise her husband by taking him out to dinner. I told her I'm totally free (as I planned to come anyway!), and she said she'd look into reservations, and she asked me to please not mention anything to her husband.

I'm feeling like I won't mention anything to either of them, and I'll simply show up on the day of the anniversary. My only concern is if one of them is spending money on the surprise (advance payments for something fancy, if the wife contacts friends as well and pays for transportation, etc).

On that day I work my normal hours anyway, so I'll probably just work my normal shift and then stay and put the twins to bed. This being the case (I hope!), I won't have to worry about both of them telling me privately to show up at different times, as I'll likely already be there.

I'm not sure what to do! What would you guys do? Just wait it out and then laugh about it later with them, or try to prevent any potential conflicts that might come up?

Either way, this is a fantastic predicament to be facing!