surprise engagement

I've been asked to shoot my first surprise engagement. I'm not stranger to engagement sessions and weddings and other styles but this is new to me.

A male client is going to surprise his girlfriend at a local park. he will have friends and family there and we will be conducting a posed session immediately after.

I'm trying to figure out how best to get in position for the surprise- should I rent a long lens and hide or should i stage a mock shoot with the friends? or is there some other tactic i should employ?

Probably better questions for the guy.

Is everyone out of sight until the last moment? If so...you'll probably need to be as well.

The "mock shoot" might be a good idea and provide an angle to getting everyone there without having to keep it a complete secret to the bride. It's hard to keep secrets...even with all good intentions.

Case in point...I did a surprise engagement, where the bride was thinking she was planning his "surprise" birthday party for him in conjunction with his mother...but it was really a surprise engagement party. Only him and his mom knew it was actually an engagement party. I thought I was shooting a birthday party up until about 5 minutes before the proposal took place when he came and filled me in.

It was pretty well executed...and the main reason...only 2 people knew.