When these issues pop up in public forums things can get ugly fast. On the one hand you have overzealous trad-fascists insisting that you need to be an initiate to work with the spirits, methods, or rites in any way shape or form. On the other hand you have people approaching without any traditional initiation calling themselves Santero's, Houngan's, Tantrikas, after reading a couple books and doing a few workings of their own invention. This can be rather upsetting to those who spend years earning those titles and going through the traditional initiations.
After years of navigating this issue I have come to understand it in terms of Title and Ability. The problems usually spring up when someone is equating one with the other.
For example. I work regularly with certain Loa. I do so based on my readings, instructions from initiated friends, and finally instructions from the Loa themselves. It was in fact Papa Legba who steered me away from pursuing initiation as a Houngan. He steered me directly into the arms of the Buddha - go figure. Still I serve him, Ezili, Dambhalla, Simbi Makaya, and others. At this point my methods for doing so are different than you would see in a traditional house, but they are terms that I cam to with the Loa directly. There is no problem because my relationship is based on my ability. If I was to suddenly decide that I should call myself a Houngan Asogwe and set up shop as such without ever receiving that initiation in a traditional way THAT would be a big problem because I would be claiming a title. Get it? At very least I need to make it very clear that I am claiming the title based on my own spiritual contacts and not through traditional means.
When I meet people who describe themselves as Tantrikas, yet they have no Guru or Abhisheka, I have to object. There is no Tantra without a Guru or Abhisheka. Even Siddhas that are supposedly born fully enlightened like Padmasambhava and Dattareya seek out human Guru's to call teachers so that they can show others how important the Guru is. Now, that does not mean that these folks cannot study the texts and get tips from contacts that they can incorporate into their practice. In fact I would strongly encourage people like Thelemites to study modern translations of Tantric texts for a deeper look at Sex Magic than what E&MOU gives. Your use of the tech is based on ability so there is no problem, your claim to the title however is bogus.
Think of it in terms of a medical doctor. You can study medical texts at home and even apprentice under someone personally to learn all you want to know. You may practice medicine BETTER than 99% of actual doctors, but you cannot call yourself an MD because you did not go through the proper steps. The work is based on ability, the Title is based on certain protocols being followed. They are not the same.
Now, there are very different considerations of how they overlap. There are certain pieces of tech that will only be available to those with the initiation. They may even be dependent upon the initiation itself. Certainly this is the view in Tantra, and in Christian Apostolic tradition. In fact, one Priest I know insists that to work most of the Grimoires were mostly designed to be worked by those who have Holy Orders, in much the same way that Tantras are made to be worked by those with empowerment.
If you are doing your own thing, than you have to be happy with that to some extent and not confuse your own findings and experiments with the tradition that you are borrowing from. When someone tells me that they "do Phurba practice" and than use it to cast circle like an Athame, it takes a good effort not to laugh in their face.
While you shouldn't mistake your own work for the tradition, you also should not discount it. I know a two different cases of REALLY powerful people, one a healer and one a more general Sorcerer, who lost their abilities when they traded in their own work for that of the tradition. What you are doing based on your own work may be BETTER than what you would get in the tradition. Some traditions get stale over time. Some teachers within traditions suck. I know more than a couple Lamas who are legitimate in terms of being recognized Tulkus and such, but who know less about the Dharma than many students do, and who practice even less.
In some cases, though not as many as initiates like to pretend, there are spirits, practices, and energies that CAN be dangerous when worked outside of the tradition. Again, it is all about ability vs title. Your title may enable you to work with those forces safely right off the bat, but that doesn't mean that no one can learn to work with them outside of the tradition. They just need to be warry of the danger.
Basically, what I want to say boils down to two things. If you are an initiate, be a little more respectful of those working outside the tradition, if they can do the work than that may be all that matters. If you are not an initiate, be respectful of those that are by not laying claim to a title that you do not have. If people can follow these two guidelines, than there is no problem