Major bus travel operators and IRCTC considers the SMS received while reserving ticket as valid and it is enough to show SMS during journey instead of ticket printed on paper along with any of the valid identity proof issued by competent authority. Even soft copy of ticket booked, shown in laptop/palmtop is also considered as valid e-ticket. But carrying electronic devices with soft copy of ticket has few pros and cons.
1) No worries about printing ticket, it saves paper
2) No question of forgetting as we are addicted to mobile phones
3) SMS usage has become quite familiar among all generations
Cons:
1) Battery may be discharged
2) Mobile phones are lost or stolen in the last minute rush
3) SMS may not be received by passenger due to network congestion or some technical problem
4) SMS may be deleted by mistake which will be treated as travelling without ticket
5) Few bus travel operators during the time of festival or holiday season may try to bluff actual passengers by selling tickets to others at a higher fare giving reason bus has left or the SMS ticket is of other bus
In case of IRCTC SMS tickets, the passenger not being able to show the SMS ticket either due to loss of mobile phone or battery discharge can show the valid identity proof to the on-board ticket checking staff and get EFT by paying Rs 50 as penalty per ticket. But searching of berth (in case of loss or battery discharge) without having idea of exact berth location, only with valid identity proof will be difficult as there can be more than 500 people with reserved tickets will be travelling in train. Be aware or make a note of PNR number somewhere while travelling as it avoids unnecessary tensions even if mobile phone is switched off!