While the blending of different cultures, practices, and beliefs is something beautiful and wonderful and totally awesome, it's important to be mindful of how you go about doing so. Cultural appropriation is a big problem and hot topic of debate within the pagan community, and for some cultures, it's extremely detrimental to their preservation, significance, and growth. If you want to incorporate practices or beliefs that are exclusive to a culture you have no claim to (ex: aboriginal, Native American, Romani, Irish, Polynesian, Hindu, etc.), get educated! Ask questions, do research, and get hands on with your learning; seek out friends and people who are active participants within that culture, and learn what is ok/not ok to "borrow" for your beliefs and incorporate into your practices. Not only does it show a great depth of integrity and respect for the culture, but it is a much more rewarding experience for your spiritual development and journey.
On the flip side, for those finding themselves victims of cultural appropriation, patience is key to surviving the face palming, and keeping your blood pressure at healthy levels. That, and remembering that 9 times out of 10, ignorance is to blame. In cases where you're dealing with an appropriator (?) who is blatantly refusing to accept that they are appropriating, being disrespectful, and refuse to reeducate themselves, the only thing you can do is provide them with the proper resources, point them in the right direction, and pray that they'll eventually be smart enough to head down that road and see for themselves the damage that they're doing...both to their own beliefs and practices, and to the culture they're inadvertently disparaging.