“You are causing me to stumble.”  It was a common joke at my Christian college, because the concept of stumbling blocks was so common.  One set of female dorm suites wore T-shifts referring to themselves as the “stumbling block in the corner.”  It was very important to avoid being the cause of another person’s sin

“But take care that this liberty of yours does not somehow become a stumbling block to the weak.” 1 Corinthians 8:9 NASB

In context, Paul is discussing food sacrificed to idols.  He is saying that even though it is actually no big deal, make sure you are not going to make someone else sin for whom it is an issue.In the context it was presented to young evangelicals, this passage was regulating the behavior and appearance of young women.  “Tank tops are not really a sin, but you don’t want to cause your brothers to stumble, do you?”  My college was not fundamentalist and there was no dress code.  We had liberty in Christ in addition to some subtle guilt.

Modesty, in evangelical world, was optional, but not really.  Yes, you can still be a Christian and not follow the rules, because we are not legalistic.  However, if your heart is in the right place, you will know to follow the rules anyways.  Only men have impure lustful thoughts.  Its totally their own responsibility, but you can help prevent stumbling by wearing modest clothing and acting less sexual.  Actually, in the long run, men want to be with a woman who is spiritual and modest, which should totally be your goal, because being wanted by a godly man is totally what makes you valuable.  However, you shouldn’t do anything that might make you look like you are trying to be attractive.  But don’t be unattractive, because that’s unfeminine, and you were created to be a Godly woman. Don’t be ugly or wear unflattering clothing, but don’t look like you are putting effort into your appearance, because that would be vain and no one likes that.  Just be effortlessly hot and wear pretty but modest clothing and don’t draw too much attention to how pretty your modest clothing is.  Easy enough, right?