http://www.capitol.state.tx.us/cgi-bin/cqcgi?CQ_SESSION_KEY=SOGNEEVOQKNV&CQ_QUERY_HANDLE=125792&CQ_CUR_DOCUMENT=59&CQ_TLO_DOC_TEXT=YES
CHAPTER FOURTEENARREST WITHOUT WARRANT
Art. 14.01. [212] [259] [247] Offense within view
(a) A peace officer or any other person, may, without a warrant, arrest an offender when the offense is committed in his presence or within his view, if the offense is one classed as a felony or as an offense against the public peace.
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Offense against the peace typically is construed as rioting (Arizona has a similar provision, as I mentioned).
Let's wait and see if that law firm has any comment.
--Boot Hill