Using uint to exclude negative values is one of the most common mistakes, because underflow wrapping is the default instead of saturation. You subtract a big number from a small number and your number suddenly becomes extremely large. This is far worse than e.g. someone having traveled a negative distance.
replyIn C# I use the 'checked' keyword in this or similar cases, when it might be relevant: c = checked(a - b);
replyNote that this does not violate the "Parse, Don't Validate" rule. This rule does not prevent you from doing stupid things with a "parsed" type.
In other cases, I use its cousin unchecked on int values, when an overflow is okay, such as in calculating an int hash code.