If you are dealing with a broker that hates profitable traders, then it's not the pips, it's the amount of money you are making that gets their attention. A hundred pips per day trading
microlots (about $10 profit, depending on pairs traded) won't get any attention. A hundred pips per day trading full lots (about $1000) will definitely get your account noticed by the nastier bucketshops.
You have to watch the broker's terms VERY carefully. Some places ban
scalping, but the definition varies widely from broker to broker. Some say any trade open for less than 20 seconds is
scalping. I've seen one that says any trade manually closed in under 10 minutes is scalping.
You can reduce your chances of problems by making sure your broker is properly licensed and regulated. Brokers that are NFA (US) or FSA (UK) are usually considered "safer", but there are other regulators and there have been some bad incidents with NFA and FSA registered brokers.