1) It's totally acceptable for an adult to dress up for a Halloween party, or to trick or treat with the kids. My beef is with the grown-ups that dress up in costumes for no particular event, you know, just for work, or to go to the gym or Walmart. Why? Just to pay homage to the holiday? Now, there's an exception to the dressing-up-at-work rule: if your entire office is dressing up, then it is ok to indulge in the costume.
2)I love seeing my friend's tiny babies in their costumes. And even when they try to not accept candy, I will certainly press it upon them. What I'm against is total strangers bringing their babies trick or treating to my house, babies who aren't even close to eating solids. And then its not like "Hey, we're just taking out baby out for everyone to admire." It's more like: no greeting, just out-held trick or treat bag, waiting for candy. If you think this scenario is unlikely, come to my neighborhood for 2 hours and you'll believe it.
See I'm not a Halloween Scrooge! (Maybe just a bit inhibited) We've got pumpkins carved and lit on the porch as I type. We'll be home tomorrow night with the light on, ready to give out candy, even to the freaky people.
PS Thanks to everyone for their comments, you know I love a controversy!