Strictly speaking, in a regular dancesport competition scored by the skating system, there are no points deducted for anything. In rounds prior to the final, couples are given either an "R" (recall) mark from each judge in each dance, or are not given anything. In the final, couples are ranked by each judge in each dance using the placings 1 through X (where X is the number of couples in the final, usually six).
Now, the wrong shoes (or dirty or excessively worn shoes) will not impress some judges and they may use that against you when deciding when to give you an "R" or where to place you in a final. But it's not like there's a score sheet where the judge writes down "bad shoes, minus 5" or anything like that.
Just wanted to point this out, as some participants, especially new ones, in dancesport don't have any idea how dancers are marked or what the marks mean. When they hear things like "you'll lose points" they might get the idea that there is an actual point system, which there isn't. A judge might keep a personal mental point system to help sort out where to place couples, but there's nothing official and nothing is recorded other than the "R" marks and the placings in the final.
