In the state of Texas it is illegal to consume alcohol in public. Walking down the street, sitting in front of your house, at the lake/river, technically it's illegal. Why do you think they give you brown paper bags with 24s? The general rule of thumb is, don't be a jackwagon and they will leave you alone. I've never had a problem, unless you are at Garner State Park. They will ticket you no matter what.
You can be ticketed for having an open container in a vehicle. However, unless you are actually over the limit, you will only get a ticket and not go to jail. However, open containers are a great way for cops to interrogate everything else about you. Open container != DWI.
At one point in Texas, it was legal to drink and drive. If you were pulled over drinking, drunk or not, the officer would ask for your beer, he would put it on the roof of your car and write you a ticket for whatever you were pulled over for, he would then hand you your beer and tell you to be safe.
As for the no-refusal stuff, I heard different. I saw something over the new years about the no refusal on those digital highways signs. Didn't provide any details though. From what I understand about this new stuff is, you can still refuse a breathe and blood test. In this case, as it was before, your license will be suspended automatically for a year for refusing. The only way they can get your BAC is to draw blood WITH a warrant. For these weekends, they have had a judge on stand by dedicated to issue warrants to draw blood for refusals. So technically you can still refuse, but they are fast tracking the issuance of warrants to draw blood. I could be wrong, but I think that is how its playing out now.
On a side note, they are also currently working to legalize DWI checkpoints in Texas too. It is currently illegal.