Most of you would have heard of travel prayers, most of you even offer it while traveling. Its basically shortening of the regular prayers (e.g. 4 units of Noon prayers reduced to 2 units) so as to provide a convenience to travelers.
Let me show you the verse in Quran that allows so...
4:101 - When ye travel through the earth, there is no blame on you if ye shorten your prayers...
No in fact. Read the whole verse.
4:101 - When ye travel through the earth, there is no blame on you if ye shorten your prayers, for fear the Unbelievers May attack you: For the Unbelievers are unto you open enemies.
Things a bit clear now? You are only allowed to shorten the prayers if you fear you'll be attacked. Its not like when you pack your bags for another city you keep shortening your prayers.
And please do not tell me that Prophet Muhammad told muslims to do so...
10:15 - But when Our Clear Signs are rehearsed unto them, those who rest not their hope on their meeting with Us, Say: "Bring us a reading other than this, or change this," Say: "It is not for me, of my own accord, to change it: I follow naught but what is revealed unto me: if I were to disobey my Lord, I should myself fear the penalty of a Great Day (to come)."