It is human nature to automatically attempt to analyze all incoming data, regardless of source, in order to determine how it affects you who is perceiving the incoming data. Depending on the nature of the data, this analysis process occurs across a wide spectrum and is often unconsciously dismissed as irrelevant to the person in question. Bottom line, most humans prioritizes themselves and there personal sphere of influence. Relevance to the topic being that this priority of focus, which few exceptions, includes even the most motivated evangelical folks.
Perhaps the declaration of intention to “pray for you,” was random unsolicited advice based on a simple chance encounter. Perhaps it was a knee jerk reaction, based on being triggered by any number of things which rattled there comfort zone. In most of these cases, it was unlikely to be anything to cause concern.
Regardless, I personally do not view most prayer offers as an intention to initiate spiritual warfare. As with most other social interactions with strangers which venture into areas I choose to not discuss, I simply de escalate and disengage. Most folks involved in such chance interactions, regardless of perceived unpleasantness, won’t give much more than a very brief period of thought to it.
Even if the conversational adversary was a minister with a active & large congregation… Unless you escalate excessively and truly cause a great worry, most often it will end there. Reason being the focus point from the first paragraph…
So barring an unnecessary conflict, the (temporarily) triggered minister will move on with his concerns of higher priority. Such has visiting sick church members, comforting grieving families, preparing the sermons for the week, etc… Basically staying focused on their sphere of influence and their personal business.
Of course, this is situationally dependant and may very well be something more serious. Especially if the environment where this occurred is for example at a highly charged venue such as a major civil rights event. These situations are increasing in frequency these days, and actually trained highly polarized groups have and do travel to engage in spiritual conflict.
@KurtisJoseph spoke on such a situation he was involved with somewhere in Texas. That said, these kind of intense events tend to be sought out and do not often occur willy nilly.
In either case, having strong spiritual allies and a well thought out protection strategy leads to a lack of worry.