we took ds girlfriend on holiday to DLP with us last year and at the time they were both 15 and we created some guidelines at the outset of the trip, trying to make sure that we spent some time with them and they spent some time together in the park or in the village and it went really well. We would set off to the Park together in the morning, perhaps go on a couple of rides and then go separate ways and meet up for lunch and do stuff together until the parade and then separate again until tea time and then we'd pretty much stick together. We always had our evening meal in the village so they would eat with us and then go off and browse for a couple of hours or use the pool at the hotel and I have to say it worked really well. I was very nervous about letting them do their own thing but they had no problems whatsoever and they both felt safe and confident doing what they were doing whereas in this country we taxi them around rather than letting them use buses, etc etc just due to the way things are. I'm sure if you have some guidelines before you go things will be just fine while you're away. I also wouldn't worry too much about leaving your pushchair, we've left ours without any problems and on one occasion we even left a bag containing all our euros, passport, camcorder, etc all sitting on the pushchair without any problems ... not that I'd recommend this, hubby nearly had to get off IASW half way round due to me panicing when we realised what we had done ! Some people let their guard down like you say and I have to say it's awful when you see a child missing but as long as you're careful you shouldn't have any problems.