I accidentally walked into Battle Tower and into a room where I ended up fighting. THe good was I was able to use 6 Pokemon, but the bad was when I fought in the 2nd round, 5 of my Pokemon just disappeared and I had MIssingno on my team! Then after I turned on the game again, May became the woman in Battle Tower and Brendan was there, and the whole Battle Tower building glitched into a broken universe where I can't move my character and each time I activated the computer, another computer appeared. Luckily I already finished Ruby anyway. But if ever using a code like that:
Don't save the game if you are 'through trees or walls'.
Don't walk through the receptionist in Battle Tower and go into the 'elevator', that's the actual room to fight.
Just for fun though, in playing a new Ruby game, I was able to walk to Mauville without fighting anybody to get my bike. The outline of the game is unique in walking on top of mountains, trees, water, but got to be in a 'normal area' if you want to save.