There are of course placed where Vaseline or any mineral-oil greases or greases based on synthetic hydrocarbons should not be used. One particular case is elastomers used with brake fluid (especially polygylcol based) as in that situation in contact with the fluid it will cause substantial swelling of the elastomers and likely brake failure (a small amount - less than 10% is actually desirable and this is achieved through the brake fluid and its additives). And generally if there is a special lubricant available for a particular purpose, it should be used over Vaseline or any other general purpose lubricant.
Yes; Vaseline does dissolve pure latex so there some risk if used as a personal lubricant with a latex condom (but the Pope may approve). Also note on Page 41 of this document
http://www.google.com.au/url?sa=t&rc...xgW9IHrI-F9WKA BTR recommend the use of Vaseline on the transmission sump gasket. It is often recommended in such situations as it provides a temporary adhesion with some improved sealing and once heated any excess is dissolved harmlessly into the transmission fluid. It's also water repelling. Similarly, when used to prime an oil pump it will dissolve harmlessly into the oil once the oil gets warm. Generally where fuel, oil or similar natural oil based products are involved Vaseline is a safe assembly lubricant for elastomer/rubber parts and seals.