We are only going away for a week in a caravan paid for by my parents. It's not much but we are soooo looking forward to the break and DH has a really stressful job and needs the break. His sister has decided to book a hotel near where we are staying and join us for a couple of days because 'it will be nice' for her son. He's a toddler and my kids tend to play with him and keep him amused.
I'm not really happy about it because the holiday was booked for us to get away and not to amuse someone else's toddler. DH is furious too.
Am I being anti-social or do I have a reasonable case to tell her not to come? If so, how can we let her down without damaging family relations?