Reverse enginering for compatibility is totally legal in the EU.

What we are doing here is probably legal in the US aswell, as far as I've managed to understand [Link: chillingeffects.org].

Also, this project should be good for Pronto aswell:
1) It will allow to send combined IR from TSU to RFX, like the airco devices that send all states (cool/heat, fan speed, angle, temperature, etc) in a single 1 command. if the port isn't open all the time.
2) It will allow TSU to talk to openremote (open remote module for TSU)
3) It should make RFX and TSU's market bigger if someone does continue the Pronto brand.
4) It should extend the TSU and RFX useable lifetime if Pronto is discontinued.

Besides the above, what good would it do for Pronto if people buy "extenders" of another brand? Now the extenders would be usable with OpenRemote (and other software), from a PC, smartphone, tablets and all other UDP capable remotes (AMX,Crestron, etc).