Tizen applications for mobile devices can be developed without relying on an official Tizen IDE as long as the application complies with Tizen packaging rules.

Still, is this declaration enough to gain trust in the community? Just before the release, Carsten Haitzler aka rasterman, Samsung's Principal Engineer working on Tizen and EFL guru in one person, showed some signs of irritation (an excerpt from an Tizen IRC log, original typos corrected):

tizen is not meego or maemo, it is not related
i've been working on this os now for like over 4 years
i have spent years saying "release ports to existing products"
no action, years saying what you say, i don't bother anymore
what will happen — will happen
i have no chance to change it because at least [in] samsung all decisions are top-down
ie. some executive with zero connection/knowledge of OSS is going to decide all the technical details
as i mentioned tizen is SLP [Samsung Linux Platform], SLP is a continuation of Limo
Limo is something that existed alongside and/or before maemo did
it has been in competition internally, no ball was picked up, it's a separate ball
it was renamed to tizen and put under a [Linux Foundation] banner and Intel then joined in
Intel has pushed for things to be much more open and to use OBS [Open Build System] and much infra that was used before for meego
[..]
tizen uses enlightenment and efl, thus why its then "zero porting" :)
that doesn't mean you will be able to use efl in apps you port/write
i do this for my own amusement, YOU may be stuck with a phone that is locked down and that doesn't allow installation of native apps at all

Shortly after that rasterman shared his look at the openess of the Linux Foundation-backed project in more depth to fight some misinformation:

Tizen, and what is in it (technically), is controlled by/decided on by the TSG [Technical Steering Group]. The TSG is a committee of executives (Samsung and Intel — you can read up on it — Imad and JD). They decide what will happen, and that's how it works. It's a top-down thing with VP's in charge. How and what they decide is up to them entirely. I have no idea what they will decide, when or where. Well officially I don't. What I may, or may not know is simply rumour and not for me to disclose, as decisions are made by the executives in charge (as above) as they see fit (which is not here in public, like on these mailing lists, IRC etc.). This (Tizen) is not like open source projects (let's say like E/EFL, Qt, GTK+, Xorg, Linux Kernel etc.), where I, or any developer, is free to talk about plans for the future and work being done, (or for that matter even knows or can find out). I understand that you are coming from that perspective, and thus logically asking those questions here, expecting answers like you would with pretty much any OSS project, but Tizen is not like that.

On the day of the release once the secret has been disclosed, rasterman concluded the reason for frustration on the Tizen IRC channel to the fellow engineers:

jooncheol Open Services Platform !!!
jooncheol bada !!
jooncheol hmm
jooncheol bada ...
jooncheol omg
Stskeeps looks like a good compromise, EFL on the inside, OSP on outside
raster hehe
* Stskeeps envisions raster being taken away in a white straightjacket to the funnyfarm
raster they did that years ago
raster i then escaped
raster and wrote a wm
raster and trust me
raster its not efl on the inside
raster efl is nothing mroe than a glorified wrapper around windows and then a simple surface compositor
Stskeeps sorry to hear that
raster everything else above that is not efl
raster so u may want to reserve judgment until u've seen it all