I agree 100%.
I also don't like the idea that guys post their sources either.
It takes alot of hard work and time to find the best vendors and best prices with the best quality product. Most of the vendors that are being named on here, along with prices, sell to the general public as well. No the general public may not get the same prices due to volume but if they can get the same products, price may not matter.
There are alot of new names on here this year, that's great, but it also means that there are that many more that are on here and not posting, you never know if the info you just posted cost you a job because a homeowner saw where you got the product or if the local handyman saw your prices and lowered his bid to beat yours...
Christmas Decorating is as close to being an electrician as we can get, dont water down or compromise the value of what we do by posting things that you shouldnt and not thinking that the internet is there for everyone.
I can go on and on about posting prices, vendors etc but I will just say this....
If you wouldn't tell you competitor the information you are about to post, then dont post it. I know I would never tell my competition where I get my product, what I pay for it or what I charge to install it....