Well, same application and network is not enough. Different phones havfe different configurations that work for them in Java. Being able to browse using the microbrowser is not a guarantee that the networking will work with MIDlets. They often have different configurations.
The only difference with MIDP 2.0 is those permission attributes in the jad but I've deployed without them many times and didn't have problems. The SecurityException will be thrown only if the user declines the permissions. Since I always catch Exceptions (as opposed to IOExceptions) that never caused problems.
Still, if you want to request the permissions it's pretty simple: