First, it all depends on the markets in which the product will be sold, then it depends on the level of liability with which the client is comfortable and then lastly, how much money does the client want to part with in order to determine the product's safety likelihood.
In the US, having product UL registered is optional in most categories (medical, government use, etc require certain certifications but for sale-to-the-public in most retail stores those certifications are not required).
You can bypass the actual process that UL uses to certify products for fire / burn / melt safety by using already-UL-certified materials and with proper design and location of internals. We often deal with UL, CSA and most of the other certifying agencies and know how to get through the landmines as efficiently as possible. Let me know if we can help.