As long as this low level character is actually someone's 2nd main character, it should be fine.
In naschat a few months ago, this was brought up and Nas noticed that Sov (I think) had a mule out somewhere and got rid of it, since he knows Sov has 2 real main characters. Sov responded by saying "but I only had 2 characters out" and Nas said "no, 2 characters out of town ever", which it sounds like was a good clarification to this issue.
Here are the logs...
Dec 08 19:37:42 sov> Until the claim system is fixed alts will continue to be brought to HNM camps
Dec 08 19:37:48 sov> this is not the first time.
Dec 08 19:37:52 * TKDKid has quit (Quit: I'll be back...)
Dec 08 19:38:11 nasomi> funny
Dec 08 19:38:12 nasomi> that's your alt
Dec 08 19:38:22 sov> yup
Dec 08 19:38:25 Vex> Morinasu, if i had to guess, none of the battlefields work right now
Dec 08 19:38:26 nasomi> tsk tsk
Dec 08 19:38:30 nasomi> 2 characters in the field
Dec 08 19:38:32 * TKDKid (
[email protected] ... global.net) has joined
Dec 08 19:38:32 * TKDKid has quit (Quit: I'll be back...)
Dec 08 19:38:41 Vex> my battlefield has me stuck atm
Dec 08 19:38:44 shalashaska> Hi, just to say the 1st telepoint at prom dem still does black screen
Dec 08 19:38:44 Morinasu> i did ZM4 yesterday, it worked fine
Dec 08 19:38:47 sov> 2 chats in the field at a time yup
Dec 08 19:38:52 nasomi> no, not at a time
Dec 08 19:38:54 sov> chars*
Dec 08 19:38:54 nasomi> ever
...
Dec 08 19:39:31 sov> when did this rule change?
Dec 08 19:39:32 Chase> Maybe there's an issue since the Maint. Nas?
Dec 08 19:39:34 Boogieman> it didnt
Dec 08 19:39:36 nasomi> never changed
...
(also, boogieman is funny)
Mar 12 20:39:48 help> but the rule has still always been 3 total chars
Mar 12 20:39:54 Boogieman> no it hasnt
Mar 12 20:40:03 help> thats what nas has said