I do both as well. On the rare occasion that I cook for others, I tend to buy the sauce. But, if I was to vend and not make my own sauce, I would either put it in a warmer (crock pot on low) or put it in squeeze bottles. I would never claim it as my own, but, I would be vague as to what it is. The exception would be if I was using a sauce from someone that I support, such as Big Butz, in which case, I would make it clear that I am featuring Big Butz sauces as long as the maker approved. I would not do that if he did not approve. One of the reasons for repacking into squeeze bottles.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."