I text at gun shows all the time. Most of my buddies are to lazy to go with me so they just tell me "hey if you see something you think I like let me know" I know they'll pay me back so I dont care but here's the problem with talking on the phone at the shows.
1) Sometimes the signal is poor and while a text will go through a conversation is is garbled.
2) A lot of dealers think you're doing a straw purchase because you're telling a friend "Hey this guy has your mags". Even though mags or ammo are not considered straw purchases. Sometimes Ill ask "My friend is looking for this do you mind if I call him to let him know?"

3) Its easier to write "9mm $5/box y/n" then to wait for the phone to ring and start a 5 min conversation beginning with Hi Im at....