Submit pages 30 minutes apart or it's spam?

Is this true?

[webtamers]

Hi Folks,

I just read the following quote on WebDevelopersJournal.com

"One major problem is that some engines do not want more than one page submitted to them from the same domain within a 30-minute period. They're set that way to catch spammers."

Is this true? I'm well aware of the daily limits for each search engine, but will usually submit the "5 per day" or whatever about a minute apart with DumpTruck. I am in danger of being penalized as a spammer? Would really appreciate your opinions.

Thanks in advance,
Chuck West

[littleman]

It has never been a problem for me.