On daf10b, Bais Shamai and Hillel argue about whether krias shema has to be said while sitting. ON daf 11a, the Gemara states a story with R' Elazar ben Azarya and Rav Yishmael. R' Elazar was standing and R' Yishmael was sitting. When it came time for krias shema, they swapped positions. R'Yishmael said that he stood up because he holds like Bais Hillel and also so that the talmidim who were watching should not get confused and assume that the halacha for doros is that they should only be allowed to sit.
On daf 30a, regarding tefillas Haderech, R' Chisda holds that you must stand in one place and Rav Sheshes holds that you can continue traveling while saying it. The Gemara says story where Rav Chisda did like his shita and stopped in order to say Tefillas Haderech, and when Rav Sheshes heard what was happening, (Rav Sheshes was blind), he decided to also stop to say it, stating "I might as well do it now".
First of all, why wasn't Rav Sheshes worried that the halacha would be established like Rav Chisda, since even Rav Sheshes did like him? Secondly, in the previous story, why couldn't Rav Gamliel say that "I might as well do it in the preferred way which covers all shitos"?
So far, I got an answer. Perhaps there was no one else watching in the second story. However, at least the shammas was there. Perhaps you have another insight to explain this discrepancy.
Yehoash Orange, Brooklyn NY
In the argument between Rav Sheshes and Rav Chisda, Rav Sheshes agrees that it is a good thing to stop and say Tefilas Haderech. Rav Sheshes merely rules leniently that one does not have to stop traveling to say the Tefilah. If the Halachah would be established that one should stop to say the Tefilah, it wouldn't be taken as anything other than the well known Halachic (and common sense) principle that one should be stationary while reciting Berachos in order to have better Kavanah.
However, the argument between Beis Shamai and Beis Hillel is a matter of a Gezeiras Hakasuv, not one of better Kavanah. It is important that we should correctly understand the Pesukim and the Halachos that they tell us.
Regarding your question of doing like Beis Shamai covering all Shitos, there are many who address this issue. The Gemara indicates that this is not your average argument, as it says that someone who does like Beis Shamai is Chayev Misah. Some say that this is because the argument between Beis Shamai and Beis Hillel is a very weighty argument in Klal Yisrael, and doing like Beis Shamai is like creating two separate Toros. It was definitely incorrect to be stringent like Beis Shamai, and this is the Halachah today (see Shulchan Aruch O.C. 63 that it is forbidden to do like Beis Shamai even today).
A gut moed,