Wiktionary defines the verb "понаехать" as follows:
наехать, приехать во множестве, в большом числе
This is obviously a single meaning, not a list of different meanings, because different meanings are given in Wiktionary as a numerated list rather than a single line with commas. In Wiktionary, a single line with commas lists synonymous phrases or synonymous words to give an idea about the meaning.
Since "наехать" is given as a synonymous word, I also looked at its definition in Wiktionary:
столкнуться при езде, сбить при езде
проехать или встать колесами на что-либо
приехать внезапно, без предупреждения
пренебр. приехать в большом количестве, обычно вопреки желанию местных
жарг. начать оказывать давление, обычно с целью заставить выполнить какие-либо требования
спец. кино, видео при помощи трансфокатора приблизить объект съёмки; плавно перейти на более крупный план
Obviously, the meaning of "наехать" in the definition of "понаехать" is the fourth meaning above, because it coincides with what is written further in the definition of "понаехать."
Thus, Wiktionary basically defines "понаехать" as "to come in big numbers."
And here is the problem: Wiktionary shows the conjugation of "понаехать" as follows:
Я понае́ду понае́хал понае́хала
Ты понае́дешь понае́хал понае́хала
Он понае́дет понае́хал
Она понае́хала
Оно понае́хало
Мы понае́дем понае́хали
Вы понае́дете понае́хали
Они понае́дут понае́хали
Пр. действ. прош. понае́хавший
What I cannot understand is how a single person can come in big numbers. The very definition of "понаехать" as it stands in Wiktionary excludes using this verb in any single person form. From a logical standpoint, only plural forms of this verb are permissible, yet single person forms are provided in the conjugation table.
I did some research in Google and found that "понаехать" is quite often used in single person forms, for example:
Сейчас я понаехал в Великобританию на второй семестр и буду рассказывать и об этой стране тоже. (Source)
This led me to suspect that the definition of "понаехать" in Wiktionary is wrong. I am very puzzled. Overall, I'm confused by this crazy combination of two prefixes.
My question is this: What is the precise meaning of "понаехать," and who is wrong - the Wiktionary contributors who defined "понаехать" as "to come in big numbers" or people who use "понаехать" in singular person forms? I'm also curious as to how the meaning of "понаехать" is different from the fourth meaning of "наехать" if there is any difference.